Rifle Barrel Length

Rifle Barrel Length

Postby hammAR » Sat Dec 03, 2011 12:45 pm

“All Great Truths Start as Blasphemy” -George Bernard Shaw


Appropriate barrel length for sniper rifles has been debated at length in tactical communities and online forums alike. In the spirit of GPS Defense’s teaching principle of deciphering the truth out of the piles of opinions by testing a theory and seeing the results first hand, we decided to put the barrel length issue to rest.

As our previous students can attest, and as you will experience in any of our classes, we often choose to prompt our students to figure out the answer to a question or previously held belief on their own. Chances are, we have encountered their question or opinion many times before and we have learned that the reason they are led to believe a certain point is simply because somebody else told them it was so. If we do the easy thing by simply telling them the correct answer, the truth we tell them will have no more weight in their mind than the possibly incorrect information that has been unquestioned and passed down from person to person.

Simply put, barrel length (within reason) does not affect accuracy within a manner many people believe. My personal rifle, based off of a Remington 700 action, has an 18″ .308 barrel. When people see my rifle, they often ask, “How much does that affect the accuracy?”

Their question, although a valid one, is usually asked in such a way that assumes accuracy must have been compromised in order for the barrel to be so short. The exact opposite is true.

My rifle came from the factory with acceptable sub minute of angle (less than 1″ group per 100yds) accuracy out of a 26″ barrel. I had my barrel cut down to 18″, took it out to the range and was pleasantly surprised to see the accuracy improve to a 1/2 minute of angle. Yes, you just read that right… the shorter barrel was more accurate.

When I dropped off the rifle to have it cut and re-crowned from its factory length, the gunsmith asked how short I wanted the barrel to be, and when I told him 18″, he tried his best to talk me out of it. He explained to me that 20″ is a “safe” length and about as short as he has seen people go while maintaining accuracy. I decided that since I was cutting the barrel to create a more manageable and compact shooting platform and partly to prove a point, I shouldn’t go to a “safe” length…. I should go shorter.

A common argument I hear from disbelievers revolves around some sort of belief that the twist rate must relate to the barrel length. This fallacy tries to say that since the twist rate of my .308 700 PSS is 1 in 12″, the barrel must be cut to a length in multiples of 12 inches in order for the bullet to spin properly. This is absurd. If this was true, Remington would never ship the PSS from the factory with a 26 inch barrel. And for that matter, a 1911 style .45 with a twist rate of 1in 16″ would have a 16″ barrel in order to be able to hit the target.

So, if a bullet from my barrel is spinning at a 1 in 12″ rate regardless of the length, why did cutting it down increase the accuracy? The answer lies in the effect of barrel stiffness. We all understand that a thicker bull barrel will provide better accuracy than a thin sportster style barrel. From this we know that a stiffer barrel helps increase accuracy by negating excessive barrel flex and vibration. The only way to stiffen an already stiff bull barrel from the factory is to shorten it. Let me explain….

Inch per inch, the barrel’s stiffness has not changed. But when taking the entire length into account, the overall effect is a stiffer barrel. Think about a 2 inch stick that is just stiff enough to be unbreakable. Now, take a stick of the same diameter with a length of 12 inches…. it would be much easier to break. Each individual inch of the two sticks share the same rigidity, but the longer stick allows more leverage to be imparted on the stick and therefore nets less overall stiffness and more leverage.

So, by cutting the barrel, the twist rate was not affected and the barrel was relatively stiffer. The only other concern lies in whether or not the powder has enough time to burn before the bullet leaves the barrel. This should not affect accuracy since it should burn consistently whether or not it burns completely. The only problem will in fact lie in the change in velocity of the bullet.

At 100 yards, I found absolutely no change in the point of impact of the bullet from the longer 26″ original length to the new shorter 18″ length. I did, however find a significant difference at longer distances.

At our 920 yard target on our range, school rifles with standard length barrels are able to hit the target with a 34 minute of angle adjustment above their 100 yard zero. When I first shot my rifle to compare the bullet drop from my rifle with the short barrel to the school rifles, I was using 168 grain Federal Gold Match ammunition and recorded hits at 39 1/2 minutes up from my 100 yard zero. That translates into a little over 50 inches of difference between the barrel lengths at 920 yards!

After realizing that the powders used by Federal (ammo I used) and Black Hills (ammo the students use) may burn at different rates, I decided to re-test my rifle with the 175 grain Black Hills Match ammunition that our students use. When using the same ammo, my rifle only needed 36 minutes of elevation in order to hit the target. Based on changing the ammo, I had a 3 1/2 minute change at 920 yards! Using consistent ammo and consistent environments, my 18 inch barrel only requires two additional minutes of elevation to engage a target 920 yards away!

With a more manageable, compact, lighter, and more accurate rifle only requiring only 2 more minutes of angle at 920 yards, I see no reason to not cut down a barrel on a sniper rifle. Still don’t believe me? Enroll in a class and I will shoot my short barrel rifle next to yours and you can learn what happens in the manner we suggest the most… you can see for yourself.

–Ryan Cleckner, GPS Defense
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Re: Rifle Barrel Length

Postby Mike » Sat Dec 03, 2011 1:42 pm

Wow, Very interesting. I have to assume your giving up some velocity with a shorter barrel?
I'm off to the gunsmith now.
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Re: Rifle Barrel Length

Postby hammAR » Sat Dec 03, 2011 2:39 pm

I suggest reading this article. I present this as I am not a ballistics expert, just a trigger puncher, and it would be futile for me to discuss. We do have others in the community that are far more qualified to answer your question, but in the mean time this may help.

I will say that in shooting the course with a shorter barrel that there is very little difference. Accuracy is not an issue for these short barrel rigs - if you use quality, prepare everything correctly, and as long as what is going on between yours ears is good, you will hit your target.

BARREL LENGTH AND THE PRECISION RIFLE Why shorter barrels may often be better by Eugene Nielsen
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Re: Rifle Barrel Length

Postby jgalt » Sat Dec 03, 2011 3:26 pm

My understanding is that the "ideal" barrel length - i.e. the length that will give you the "best" terminal performance or ballistics (depending on whether you are shooting meat or paper...) - is the one where the bullet shot reaches it's maximum potential velocity just as it leaves the barrel.

If hypothetical rifle "A", using hypothetical ammo "X" has an "ideal" barrel length of 22", then:

- A longer barrel won't help, and could hurt, as all the energy from the powder has been spent, and as the first article in this thread stated, there is more room for the barrel to affect the flight of the bullet.

- A shorter barrel will allow the bullet to leave before the max potential velocity of the round has been reached. This will obviously give less than "ideal" ballistics & terminal performance for the bullet.

*** While there isn't any tangible benefit (other than a longer sight radius, which isn't typically a factor anymore with most folks using optics...) to a longer than "ideal" barrel, there are a number of potential benefits to a shorter barrel, including less weight, easier handling, etc...

*** "Ideal" terminal performance &/or ballistics - within reason, of course - is rarely important in the real world. The max distance a 308 can travel before it loses enough velocity to start to tumble isn't that much different for a bullet fired from an 18" barrel than it is for a 22" barrel. This will only matter if you are taking shots that are at least 900 yards - and potentially 100-200 yards farther depending on the ammo used - and lets face it, most of us aren't shooting at anywhere near those distances. Same issues for terminal performance...

As also noted in the original article, the type of ammo used will almost certainly have a much larger affect on both performance & ballistics than will barrel length. Stated another way, the length of your rifle's barrel will almost certainly have an affect on the ammo purchased or loaded, but once the "right" ammo for your barrel length is found, your performance / ballistics will be effective for what you are trying to accomplish.


Now please, if any of the above is incorrect or incomplete, do chime in... 8-)
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Re: Rifle Barrel Length

Postby rugersol » Sat Dec 03, 2011 4:37 pm

I read, years ago, that "a longer bbl tends to whip". 'Tween that, and my preference fer the feel of a shorter rifle, I've always gravitated, that way.

I've been an early adopter on a few "innovations" ... not the least of which, the WSM's. To this day, I see nothing that dispels its claims. The RCM's are WSM's, marketed a bit better. I don't think they publish it anymore, but when they did, it was a comparison of the RCM's, and comparable WSM's, both from 20in bbl's (purdy short when yer talkin' .300 and .338/.325 "magnums") ... the numbers were nearly identical. Both far superior to their traditional magnum counterparts, at 20in ... but nearly identical, to each other.

I don't think there's any question, some cartridges, as ya shorten the bbl, they lose FPS ... FAST!

Point bein', 'fore anyone rushes out to chop their 26in .25-06 antelope rifle to 18in, maybe take 'nother look at yer dope chart, and print a new one at 300fps less ... then figure out yer new margin of error at 500yd. :?

A 200yd .270 deer rifle? ... hell, if it wouldn't look so silly, I'd take it down to 16in! :lol:

As it is, my own 24in sporter .270 WSM ain't quite awful 'nuff fer me to take a saw to it ... yet.

Oh ... wait! ... 'er was this a "sniper's only" discussion? Image
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Re: Rifle Barrel Length

Postby hammAR » Sat Dec 03, 2011 4:54 pm

Incomplete...no just missing a few, but a good start and understanding......
First you have to ask what kind of ballistics; internal, external, or terminal are you analyzing?

You need to read more. Start with 'Understanding Firearm Ballistics' by Robert Rinker, 'Everyday Ballistics' by Charles Cummings, 'The Bullets Flight' by Dr. Franklin Mann, and 'Rifle Accuracy Facts' by Harold R. Vaughn. These books cover internal ballistics, barrel vibration, chamber and throat design, muzzle blast effects, bullet core problems, external ballistics and many other chapters.

My simple need and understanding is: does it do the job that is asked of it, simple yes or no.......all the rest it theory for folks to discuss....... :P
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Re: Rifle Barrel Length

Postby jgalt » Sat Dec 03, 2011 5:01 pm

hammAR wrote:You need to read more. Start with 'Understanding Firearm Ballistics' by Robert Rinker, 'Everyday Ballistics' by Charles Cummings, 'The Bullets Flight' by Dr. Franklin Mann, and 'Rifle Accuracy Facts' by Harold R. Vaughn. These books cover internal ballistics, barrel vibration, chamber and throat design, muzzle blast effects, bullet core problems, external ballistics and many other chapters.


:shock:

As if I didn't have enough to do already... :lol:

Thanks - I always appreciate recommended reading material, even if I won't be getting to it right away... :toast:
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Re: Rifle Barrel Length

Postby hammAR » Sat Dec 03, 2011 5:09 pm

rugersol wrote:Point bein', 'fore anyone rushes out to chop their 26in .25-06 antelope rifle to 18in, maybe take 'nother look at yer dope chart, and print a new one at 300fps less ... then figure out yer new margin of error at 500yd. :?
.
.
.
Oh ... wait! ... 'er was this a "sniper's only" discussion? Image


First point, not errors.....you dope any rifle for use to what the equipment will perform......
Second point, just a dumb statement......
The rest of your stuff kind of made some sense..... :P

The subject was brought up because there is a lot of BS floating out there regarding barrel length, it is for consideration and thought, not a recommendation!

.
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Re: Rifle Barrel Length

Postby rugersol » Sat Dec 03, 2011 6:19 pm

hammAR wrote:The rest of your stuff kind of made some sense..... :P

:shock:
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Re: Rifle Barrel Length

Postby Traveler » Mon Dec 05, 2011 7:37 pm

I have used this theory since my teenage years. I've always told the girls it isn't the length that counts as much as the rigidity.





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Re: Rifle Barrel Length

Postby scattergun4015 » Mon Dec 05, 2011 8:14 pm

So, my buddy has an ar sbr(don't remember which brand) with an 11in barrel and my other buddy has a bushmaster 16in. Longest we tried is 200 meters at oakdale, but the sbr holds a tighter group than the 16in bushie. Same guy shooting with same optics.....eotech with 3x magnifier. How do you explain that one? Is it just because the sbr has a better barrel? I know he spent around 2000 for it while my other buddy spent maybe 700 on the bushie
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Re: Rifle Barrel Length

Postby Ranger01 » Mon Dec 05, 2011 8:49 pm

I'm gonna guess its partly quality of parts and workmanship and partly familiarity with the particular weapon that makes the SBR more accurate.
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Re: Rifle Barrel Length

Postby hammAR » Mon Dec 05, 2011 9:23 pm

Ranger01 wrote:I'm gonna guess its partly quality of parts and workmanship and partly familiarity with the particular weapon that makes the SBR more accurate.


Add to that barrel length, twist rates, and munitions. The military, regardless of common beliefs, has a number of 5.56 munitions that they use. Different bullet type/weight and powder for M4 (14.5 or 16"), a different one for the SDM (18"), and another for the M16-A4 (20")............and depending on branch and application............

Example, for the M4 the Army's standard shipment was the M855 (62 gr) round, but found it inefficient with harder target an in longer range running gun battles. The M855 round replaced the previous SS109 round which was designed for M16's, but was ineffective in the M4 configuration as proven in Somalia. Since June 2010 they started shipping its new M855A1 Enhanced Performance Round - with improved hard target capability, more dependable, consistent performance at all distances, improved accuracy, reduced muzzle flash and a higher velocity - new bullet and powder. For the SDM they went to a Mk 12 SPR a 77-grain (5.0 g) "Match" bullet again with different powder and designed by the USMC.

Military FMJ bullets are constructed with a steel penetrator in the nose, the composition, thickness, and relative weights of the jackets, penetrators, and cores are quite variable, as are the types and position of the cannelures. Because of the significant differences in construction between bullets within the SS109/M855 category, terminal performance is quite variable—with differences noted in yaw, fragmentation, and penetration depths. Add to that the fact that the Army currently has 11 contracts out foreign nations to produce their munitions - can you say standards........ha!

So trying to compare and analyze civilian .223 munitions or an incorrect 5.56 munitions in a variety of AR style rifle may well give a lot of variations as one shoots and attempts to compare them.

Here is a list of the 5.56 munitions under contact and manufactured, as well as issued over time, application, and branch.....

Cartridge, Caliber 5.56 mm, Ball, M193 (United States): 5.56×45mm 55-grain ball cartridge.
Cartridge, Caliber 5.56 mm, Grenade, M195 (United States): 5.56×45mm grenade launching blank.
Cartridge, Caliber 5.56 mm, Tracer, M196 (United States): 5.56×45mm 54-grain tracer cartridge, red cartridge tip.
Cartridge, Caliber 5.56 mm, Dummy, M199 (United States): 5.56x45mm dummy cartridge, non firing, indented case.
Cartridge, Caliber 5.56 mm, Blank, M200 (United States): 5.56×45mm violet-tipped blank cartridge.
Cartridge, Caliber 5.56 mm, Ball, M202 (United States): 5.56×45mm 58-grain FN SSX822 cartridge
Cartridge, Caliber 5.56 mm, Ball, XM287 (United States): 5.56×45mm 68-grain ball cartridge produced by Industries Valcartier, Inc. An Improved version was also produced designated XM779.
Cartridge, Caliber 5.56 mm, Tracer, XM288 (United States): 5.56×45mm 68-grain tracer cartridge produced by Industries Valcartier, Inc. An Improved version was also produced designated XM780.
Cartridge, Caliber 5.56 mm, Grenade, M755 (United States): 5.56×45mm grenade launching blank specifically for the M234 launcher.
Cartridge, Caliber 5.56 mm, Ball, XM777 (United States): 5.56×45mm ball cartridge.
Cartridge, Caliber 5.56 mm, Tracer, XM778 (United States): 5.56×45mm tracer cartridge.
Cartridge, Caliber 5.56 mm, Ball, M855 (United States): 5.56×45mm 62-grain FN SS109 ball cartridge, green tip w/steel penetrator and a lead core.
Cartridge, Caliber 5.56 mm, Ball, M855 Lead Free (United States):62-grain green tip w/tungsten penetrator and a steel core. Primarily used during training in countries with strict lead disposal laws.
Cartridge, Caliber 5.56 mm, Ball, M855A1 (United States):62-grain green tip w/19-grain steel penetrator tip and a solid copper core.
Cartridge, Caliber 5.56 mm, Tracer, M856 (United States): 5.56×45mm 64-grain FN L110 tracer cartridge
Cartridge, Caliber 5.56 mm, Armor Piercing, M995 (United States): 5.56×45mm 52-grain AP cartridge, black cartridge tip.
Cartridge, Caliber 5.56 mm, Tracer, XM996 (United States): 5.56×45mm so-called "Dim Tracer" with reduced effect primarily for use with night vision devices.
Cartridge, Caliber 5.56 mm, Special Ball, Long Range, Mk 262 Mod 0/1 (United States): 5.56×45mm 77-grain Open-Tipped Match/Hollow-Point Boat-Tail cartridge. Mod 0 features Sierra Matchking bullet, while Mod 1 features either Nosler or Sierra bullet.
Cartridge, Caliber 5.56 mm, MK318 MOD 0 enhanced 5.56 mm ammunition (United States): 5.56×45mm 62-grain Open-Tipped Match Boat-Tail cartridge.

One thing, as a military guy always realizes, is that your weapons and munitions come from the lowest bidder............. :mrgreen:
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Re: Rifle Barrel Length

Postby goalie » Wed Feb 26, 2014 8:21 pm

Precision is not related to how much drop you have to dial.

Precision also doesn't help you if you don't know your dope or range.

I have seen amazing things with "rainbow" trajectory Sharps rifles. running a .308 with an 18" tube is child's play in comparison......
It turns out that what you have is less important than what you do with it.
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Re: Rifle Barrel Length

Postby Makarov » Tue Mar 25, 2014 1:26 am

But no bit of information was, Virgil believes, more valuable than a little advice Jim Gilmore passed along. Jim said a barrel MUST be 21 3/4” long for optimum accuracy. That precise length, he stated, sets up a vibration pattern that duplicates well from shot to shot. Virgil faithfully followed that advice on his guns
.

Above from this link: Secrets of the Houston Warehouse
http://www.angelfire.com/ma3/max357/houston.html

From same article:
For those of us who are strangers to groups “in the zeros”, we’re talking about 5 shots at 100 yards that are, at first glance, indistinguishable from a single shot. The bullets sizzling through the same hole merely worry away the tortured edge of the target paper in varying degrees until the hole is enlarged less than .100" over bullet diameter. Often much less
.
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Re: Rifle Barrel Length

Postby jgalt » Tue Mar 25, 2014 1:38 am

:popcorn:
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Re: Rifle Barrel Length

Postby Currahee » Tue Mar 25, 2014 5:02 pm

jgalt wrote::popcorn:

+1
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Re: Rifle Barrel Length

Postby Justaguy » Tue Mar 25, 2014 5:02 pm

Makarov wrote:
But no bit of information was, Virgil believes, more valuable than a little advice Jim Gilmore passed along. Jim said a barrel MUST be 21 3/4” long for optimum accuracy. That precise length, he stated, sets up a vibration pattern that duplicates well from shot to shot. Virgil faithfully followed that advice on his guns
.

Above from this link: Secrets of the Houston Warehouse
http://www.angelfire.com/ma3/max357/houston.html

From same article:
For those of us who are strangers to groups “in the zeros”, we’re talking about 5 shots at 100 yards that are, at first glance, indistinguishable from a single shot. The bullets sizzling through the same hole merely worry away the tortured edge of the target paper in varying degrees until the hole is enlarged less than .100" over bullet diameter. Often much less
.

And it MUST be a 7mm Remington Magnum.
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Re: Rifle Barrel Length

Postby hammAR » Tue Mar 25, 2014 6:01 pm

Pass the popcorn........... :beercouch:
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Re: Rifle Barrel Length

Postby Rip Van Winkle » Tue Mar 25, 2014 7:19 pm

Justaguy wrote:And it MUST be a 7mm Remington Magnum.

Pussy, everybody knows you can't hit anything without a 338 Lapua. :rotf:
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Re: Rifle Barrel Length

Postby jgalt » Tue Mar 25, 2014 7:19 pm

Justaguy wrote: <snip>
And it MUST be a 7mm Remington Magnum.


A Tikka 7mm RemMag, to be precise...
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Re: Rifle Barrel Length

Postby hammAR » Wed Mar 26, 2014 8:54 pm

Alright, enough fucking popcorn, tequila, and 7mmRM................

First off this thread is not intended to be a recommendation, but something for consideration and discussion. I am not going to get into a pissing contest, but I am going to point out some distinct facts on differences between the articles, as well as their objectives and applications, and neither involves competition.

However, to get to the end point we do have to discuss competition a little to put it into perspective – objectives and applications.

First there are two major trends in competition. One type is group shooting, in which the object is to place five or ten shots on a target as close together as possible on a target at a known distance. Winning placement in competition is determined by how well each competitor achieves this goal or in other words, how closely the shots are grouped. This is sometimes termed precision competition.

The other is score shooting, where a traditional bulls eye type target with scoring rings is used, in which the object is to place five or ten shots on a target as close to the center as possible on a target at a known distance.. Winning placement is determined by each shooter's score results. This is sometimes termed accuracy competition.

And finally there is non-competition hunting for sport or sniper duty. This is where the object is to place one shot on a target as close to a vital area (COM-COH) as possible on a target at an unknown distance in a variety of environments - call it accuracy application.

The article about the Houston Warehouse is a great read, but one needs to understand that their objective was to repeatedly put five bullets into one hole at 100 yards. It was repeatedly a perfect environment, no sun, rain, wind. Further the participants, because I can not call them shooters or riflemen, aimed specifically for highly accurate rifles, custom built, and even then they found only occasionally a rifle would qualify. They were not using just about any single-shot or multi-shot rifle, they were using rail guns. These are where 1 ½ to 2 inch rifle barrels and firing mechanisms are built into a machine, or return-to-battery rest. They are just barreled actions (the top) that ride directly on a machine rest (the base), no additional rests are needed. The base provides adjustable feet to provide a stable position on the bench, and the rifle is aimed with horizontal and vertical adjustments built into the base, then mounted on massive concrete bases. What is removed with the return-to-battery (RTB) rifle is the need to physically aim the rifle for each shot, evaluation of how any mirage will affect the shot, and in this case the affects of wind. With rifles such as these, most argue that little to no shooting skill is involved and was simply a test of the gunsmith's craft.

300px-Railgun1.jpg
300px-Railgun1.jpg (19.03 KiB) Viewed 40107 times


The objective of the GPS Defense article focuses on shooting rifle types that have recognizable stocks, and are fired from a position buy a rifleman, and that requires the set of skills of the conventional marksman. The application involves the entire rifle, training riflemen, creating new dope, and myth of general barrel length effects at unknown distances out 1,000 yards. The rifle has many differences, such as opposed to the Houston rifles that have triggers of 1/2 to 1 ounce, these rifles have a 3 pound trigger. It is mounted to the shooters shoulder and may utilize either a sling or bi-pod in combination to create the shooting platform. The the return-to-battery (RTB) is the responsibility of the rifleman and being able to repeatedly acquire and physically aim the rifle for each shot, evaluation of how any mirage will affect the shot, changing wind conditions, ambient air density, other typical factors, and of course accurately calculating the range.

The one thing that each article has in common is that nearly all rely exclusively on hand-loaded ammunition, which is user-assembled, round by round, with painstaking precision and tune it to the rifle. However, even here there are differences to achieve the shot-to-shot consistency necessary for performance. The Houston shooters use precision target grade bullets made by custom bullet makers, and are solely concerned with Very Low Drag (VLD) or Ballistic Coefficient (BC) while on the other hand the GPS Defense shooters are concerned with terminal ballistics for the one shot.

In the end, I salute the energy, knowledge and commitment of the folks involved with the Secrets of the Houston Warehouse, their legacy leaves a lot to learn. I also salute the folks involved with GPS Defense for their energy, knowledge and commitment, the lessons, and most especially surviving cutting my rifle.

M40 18in Rifle (PD).jpg


Have a blessed day and enjoy shooting whatever you choose, at whatever you choose,
but make sure that it is not me - cause I shoot back......... :toast:
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Re: Rifle Barrel Length

Postby Makarov » Thu Mar 27, 2014 2:00 am

They were not using just about any single-shot or multi-shot rifle, they were using rail guns.
snip

We must have read VERY different articles about the Houston Warehouse. I re-read the article above and did not see one mention of "rail guns" .
quote below is from article I linked to above: bold is mine.

And so began perhaps the most insightful, revealing experimentation into practical rifle accuracy ever conducted. Over a period of six years, the levels of accuracy achieved in the Houston Warehouse went beyond what many precision shooters thought possible for lightweight rifles shot from sandbags and aimed shot-to-shot by human eye.


The main thing I took from that article, in relation to this thread on rifle barrel length , was the 21 3/4 ideal barrel length.
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Re: Rifle Barrel Length

Postby jgalt » Thu Mar 27, 2014 2:32 am

While the article posted by Makarov isn't describing the rail gun hammAR pictured, it wasn't fired from anything close to a "rifleman" position either...

The quoted info below is taken from this link:

http://precisionrifleblog.com/2013/10/1 ... -accuracy/

Rifle specs:

Cartridge: 22 PPC shortened .05”
Action: Cooper
Barrel: Shilen Select Match Grade 8-groove #7 contour barrel 21 ¾” long with target crown. (Virgil said no advice he learned was more valuable than this: a barrel MUST be 21 3/4” long for optimum accuracy. That precise length sets up a vibration pattern that duplicates well from shot to shot.)
Stock: McMillan
Trigger: Burns conversion Remington trigger set to ¼ ounce

Firing Pin: As strong as feasible
Scope & Rings: Lyman-Siebert 30X scope in Bausch & Lomb rings set on Weaver bases. The rings had been painstakingly lapped so only a tiny amount of crosshair correction was needed to bring the gun on target.
Powder: IMR 4198 (load was on the warm side)
Bullets: 52gr Remington Bench Rests (since discontinued)
Primer: Federal 205M
Case: Sako .220 Russian


Shooting Technique:

Consistency is everything: After all the thousands of rounds I fired in the warehouse, I developed a technique that was practically infallible. I did exactly the same thing every shot. I was like a machine, and once you find out what works, you don’t change anything. I tried to put my fingerprint on the trigger exactly where my last fingerprint was. Consistency is everything.
Shoot free recoil: We discovered that if you want a gun to really shoot, you can’t cheek it, you can’t shoulder it, you can’t hand it, you can’t thumb it. The only thing you touch is the trigger. I didn’t even touch the bench. I planted my feet solidly on the floor and kept them right there. Your shoulder should be 3/16″ to 5/16″ from the stock so you can catch the rifle immediately when it recoils back, otherwise the rifle will get back too far and disturb the rear bag.
Rear Bag: The rear bag and the way you manage it is crucial. First, he positioned the rifle on the bench so the stock barely protruded from the “V” of a rabbit-ear bag, then he pounded the stock firmly into the bag. As already mentioned, when the rifle recoils, it’s important that the bag stay put. With proper bag technique, when the rifle is returned to its firing position, any sight corrections should be slight and made by tiny manipulation of the rear bag. The less bag adjustment, the better. The rear bag was packed very firm with casting sand, which is about 33% heavier than common sand. He then applied water and formed the “V” to the rifle stock by pounding the stock into the bag and allowing the leather to dry. Done only once, this step hardens the leather and makes the stock slide smoother. A mixture of equal amounts of talcum powder and white graphite applied to the back and front bags provided smooth sliding of the rifle, even in very humid conditions.
Front Bag & Fore-End Stop: He packed the front bag as hard as iron. Here he employed a one-to-three mixture of Portland cement and casting sand. The cement doesn’t set, but it does help hold the bag shape by resisting the twisting force imparted to the fore-end by bullet torque. No side support was used for the front bag. He strongly advocates the pedestal fore-end stop. He adjusted the stop so the front bag supported the fore-end about halfway from the end of the fore-end to the receiver. He said if the bag is positioned farther forward, this part of the stock is too springy, and accuracy will suffer. When resetting the rifle after firing, he bumped the fore-end stop and then pulled the rifle back “one-millionth of an inch.” Contact between the stop and stock tended to deteriorate accuracy.
Cleaning: Barrels were cleaned every six shots (one 5 shot group plus a fouler). They found they were able to predict where every bullet would print shot-to-shot, but that only applied if the rifle was cleaned between groups. He used a bronze brush and solvent each time, and at regular intervals the barrel had to undergo a scrubbing with J-B compound to remove solvent-resistant fouling 3″ to 4″ up from the chamber.
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jgalt
 
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Re: Rifle Barrel Length

Postby jgalt » Thu Mar 27, 2014 2:39 am

And, while taking nothing away from the results achieved by the folks in Houston, the first part of the first sentence of the OP is:

Appropriate barrel length for sniper rifles... <snip>


The guy in Makarov's article may not have been using a rail gun, but he definitely wasn't using a "sniper rifle", nor was he shooting the rife that was used in the way a sniper would.

My point - I found both articles to be interesting and worth the read, but as they were referring to two (almost) completely different topics, the information on barrel length from the 2nd article should not be seen as relevant to the information discussed in the 1st...


Back to my :popcorn: ...

8-)
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