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April 23rd, 2021

Don’t Get Caught Short — Make Sure Your Barrels Are Legal Length

short barrel barreled rifle shotgun NSA tax stamp ATF legal brief guncollective.com

The Legal Brief is a feature of TheGuncollective.com that focuses on firearms rules and regulations. In this Legal Brief video, Attorney Adam Kraut explains key State and Federal regulations governing firearms, and explains how to ensure compliance with all applicable laws.

This five-minute video explains barrel length rules for rifles and shotguns, and also explains the best (and most fool-proof) methods to measure your barrel. In addition, the video explains how to measure firearm overall length. A rifle or shotgun which is less than 26 inches overall can also be classified as a “Short-barreled” rifle/shotgun subject to the NFA. NOTE: Under federal law “If the rifle or shotgun has a collapsible stock, the overall length is measured with the stock EXTENDED”.

Highlights of LEGAL BRIEF Discussion of Barrel Length and Firearm Overall Length

The ATF procedure to measure the length of a barrel is to measure from the closed bolt or breech face to the furthest end of the barrel or permanently attached muzzle device. ATF considers a muzzle device that has been permanently attached to be part of the barrel and therefore counts towards the length.

How to Measure Barrel Length: Drop [a] dowel or rod into the barrel until it touches the bolt or breech face, which has to be closed. Mark the outside of the rod at the end of the muzzle crown (if you don’t have a permanently attached muzzle device) or at the end of the muzzle device if it is permanently attached. Remove the rod and measure from the mark to the end of the rod. That is your barrel length[.]

Remember, if the barrel length is less than 16 inches, it is possible that the firearm could be a short barrel rifle (if you are building a rifle or it is already on a rifle) and if the barrel length is less than 18 inches, it is possible the firearm could be a short barrel shotgun (again if you are building a shotgun or it is already a shotgun). Both of these firearms would be subject to the purview of the National Firearms Act and would require the firearm to be registered accordingly.

How to Measure Overall Length:The overall length of your rifle or shotgun may also classify it as a Short Barrel Rifle or Short Barrel Shotgun. The overall length of a firearm is the distance between the muzzle of the barrel and the rearmost portion of the weapon measured on a line parallel to the axis of the bore. … If the rifle has a permanently attached muzzle device, that is part of the overall length. … If the rifle or shotgun has a collapsible stock, the overall length is measured with the stock extended.

READ FULL ARTICLE on Ammoland.com.

Links for this episode:

ATF Method for Measuring Barrel Length and Overall Length:
https://www.atf.gov/firearms/docs/atf-national-firearms-act-handbook-chapter-2/download
Firearm – 26 USC § 5845: https://www.law.cornell.edu/uscode/text/26/5845
Firearm – 27 CFR § 479.11: https://www.law.cornell.edu/cfr/text/27/479.11
Short Barrel Rifle – 18 USC § 921(a)(8): https://www.law.cornell.edu/uscode/text/18/921
Short Barrel Rifle – 27 CFR § 478.11: https://www.law.cornell.edu/cfr/text/27/478.11
Short Barrel Shotgun – 18 USC § 921(a)(6): https://www.law.cornell.edu/uscode/text/18/921
Short Barrel Shotgun – 27 CFR § 478.11: https://www.law.cornell.edu/cfr/text/27/478.11

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January 10th, 2021

How to Select Proper Twist Rate for Your Bullet Size

Glen Zediker Twist Rate .223 Rem Barrel Top Grade Ammo Midsouth
Here’s an extreme range of .224-Caliber bullets: 35gr varmint bullet and 90gr match bullet. Of course, along with bullet length/design, you need to consider MV when choosing twist rate.

Even with the same caliber (and same bullet weight), different bullet types may require different rates of spin to stabilize properly. The bullet’s initial spin rate (RPM) is a function of the bullet’s muzzle velocity and the spin imparted by the rifling in the barrel. You want to ensure your bullet is stable throughout flight. It is better to have too much spin than too little, according to many ballistics experts, including Bryan Litz of Applied Ballistics. The late Glen Zediker provided some basic tips concerning barrel twist rates and bullet stability. These come from his popular book, Top Grade Ammo.

Choosing the Right Twist Rate
I’d always rather have a twist too fast than not fast enough. Generally… I recommend erring toward the faster side of a barrel twist decision. 1:8″ twist is becoming a “new standard” for .224 caliber, replacing 1:9″ in the process. The reason is that new bullets tend to be bigger rather than smaller. Don’t let a too-slow twist limit your capacity to [achieve] better long-range performance.

Base your next barrel twist rate decision on the longest, heaviest bullets you choose to use, and at the same time realize that the rate you choose will in turn limit your bullet choices. If the longest, heaviest bullet you’ll shoot (ever) is a 55-grain .224, then there’s honestly no reason not to use a 1:12″. Likewise true for .308-caliber: unless you’re going over 200-grain bullet weight, a 1:10″ will perform perfectly well.

Glen Zediker Twist Rate .223 Rem Barrel Top Grade Ammo Midsouth

Bullet Length is More Critical than Weight
Bullet length, not weight, [primarily] determines how much rotation is necessary for stability. Twist rate suggestions, though, are most usually given with respect to bullet weight, but that’s more of a generality for convenience’s sake, I think. The reason is that with the introduction of higher-ballistic-coefficient bullet designs, which are longer than conventional forms, it is easily possible to have two same-weight bullets that won’t both stabilize from the same twist rate.

Evidence of Instability
The tell-tale for an unstable (wobbling or tumbling) bullet is an oblong hole in the target paper, a “keyhole,” and that means the bullet contacted the target at some attitude other than nose-first.

Glen Zediker Twist Rate .223 Rem Barrel Top Grade Ammo MidsouthIncreasing Barrel Length Can Deliver More Velocity, But That May Still Not Provide Enough Stability if the Twist Rate Is Too Slow

Bullet speed AND barrel length have an influence on bullet stability, and a higher muzzle velocity through a longer tube will bring on more effect from the twist, but it’s a little too edgy if a particular bullet stabilizes only when running maximum velocity.

My failed 90-grain .224 experiment is a good example of that: I could get them asleep in a 1:7″ twist, 25-inch barrel, which was chambered in .22 PPC, but could not get them stabilized in a 20-inch 1:7″ .223 Rem. The answer always is to get a twist that’s correct.

These tips were adapted from Glen’s newest book, Top-Grade Ammo, available at Midsouth. To learn more about this book and other Zediker titles, and read a host of downloadable articles, visit ZedikerPublishing.com.

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June 23rd, 2019

Don’t Get Barrel-Busted! Federal Barrel Length Requirements

short barrel barreled rifle shotgun NSA tax stamp ATF legal brief guncollective.com

The Legal Brief is a feature of TheGuncollective.com that focuses on firearms rules and regulations. In this Legal Brief video, Attorney Adam Kraut explains key State and Federal regulations governing firearms, and explains how to ensure compliance with all applicable laws.

This five-minute video explains barrel length rules for rifles and shotguns, and also explains the best (and most fool-proof) methods to measure your barrel. In addition, the video explains how to measure firearm overall length. A rifle or shotgun which is less than 26 inches overall can also be classified as a “Short-barreled” rifle/shotgun subject to the NFA. NOTE: Under federal law “If the rifle or shotgun has a collapsible stock, the overall length is measured with the stock EXTENDED”.

Highlights of LEGAL BRIEF Discussion of Barrel Length and Firearm Overall Length

The ATF procedure to measure the length of a barrel is to measure from the closed bolt or breech face to the furthest end of the barrel or permanently attached muzzle device. ATF considers a muzzle device that has been permanently attached to be part of the barrel and therefore counts towards the length.

How to Measure Barrel Length: Drop [a] dowel or rod into the barrel until it touches the bolt or breech face, which has to be closed. Mark the outside of the rod at the end of the muzzle crown (if you don’t have a permanently attached muzzle device) or at the end of the muzzle device if it is permanently attached. Remove the rod and measure from the mark to the end of the rod. That is your barrel length[.]

Remember, if the barrel length is less than 16 inches, it is possible that the firearm could be a short barrel rifle (if you are building a rifle or it is already on a rifle) and if the barrel length is less than 18 inches, it is possible the firearm could be a short barrel shotgun (again if you are building a shotgun or it is already a shotgun). Both of these firearms would be subject to the purview of the National Firearms Act and would require the firearm to be registered accordingly.

How to Measure Overall Length:The overall length of your rifle or shotgun may also classify it as a Short Barrel Rifle or Short Barrel Shotgun. The overall length of a firearm is the distance between the muzzle of the barrel and the rearmost portion of the weapon measured on a line parallel to the axis of the bore. … If the rifle has a permanently attached muzzle device, that is part of the overall length. … If the rifle or shotgun has a collapsible stock, the overall length is measured with the stock extended.

READ FULL ARTICLE on Ammoland.com.

Links for this episode:

ATF Method for Measuring Barrel Length and Overall Length:
https://www.atf.gov/firearms/docs/atf-national-firearms-act-handbook-chapter-2/download
Firearm – 26 USC § 5845: https://www.law.cornell.edu/uscode/text/26/5845
Firearm – 27 CFR § 479.11: https://www.law.cornell.edu/cfr/text/27/479.11
Short Barrel Rifle – 18 USC § 921(a)(8): https://www.law.cornell.edu/uscode/text/18/921
Short Barrel Rifle – 27 CFR § 478.11: https://www.law.cornell.edu/cfr/text/27/478.11
Short Barrel Shotgun – 18 USC § 921(a)(6): https://www.law.cornell.edu/uscode/text/18/921
Short Barrel Shotgun – 27 CFR § 478.11: https://www.law.cornell.edu/cfr/text/27/478.11

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March 7th, 2017

.338 Lapua Magnum Barrel Cut-Down Velocity Test

.338 Lapua Magnum LM barrel length vs velocity cut down test chrono rifleshooter.com
Shooters contemplating purchase of a .338 LM rifle often ask: “What length barrel should I get?” Rifleshooter.com recently performed a test that provides interesting answers…

Our friends at RifleShooter.com like to slice and dice — barrels that is. They have done barrel length cut-down tests for popular calibers like the .223 Rem, 6.5 Creedmoor, and .308 Winchester. But now they’ve tackled something way bigger — the .338 Lapua Magnum, a true “Big Boomer”. Starting with a beefy 30″-long Pac-Nor Barrel, RifleShooter.com chopped the tube down in one-inch increments all the way down to 17 inches (that’s 14 different lengths). At each new (shorter) barrel length, velocity was measured with a MagnetoSpeed chronograph using two different loads, 250gr SMKs with H4831sc and 300gr SMKs with Retumbo. Four shots were fired at each length with each load, a total of 112 rounds.

Load #1: 250gr Sierra MK, Lapua brass, CCI #250 primer, H4831SC, OAL 3.720″.
Load #2: 300gr Sierra MK, Lapua brass, Win WLRM primer, Retumbo, OAL 3.720″.

READ FULL .338 Lapua Magnum Barrel Cut-down Velocity TEST >>

The .338 Lapua Magnum is a jumbo-sized cartridge, that’s for sure…
.338 Lapua Magnum LM barrel length vs velocity cut down test chrono rifleshooter.com

Donor Barrel Sacrificed for Science
Rifleshooter.com’s Editor explains: “Brandon from Precision Addiction offered to send us his .338 barrel for our .338 Lapua Mag test. I took him up on his offer and he sent me his used Pac-Nor chrome-moly barrel with about 600 rounds though it. This thing was a beast! A heavy 1.350″ shank that ran straight for 6″, until tapering to 1″ at 30″ in length.”

.338 Lapua Magnum LM barrel length vs velocity cut down test chrono rifleshooter.com

Results Summary

.338 Lapua Magnum with 250gr Sierra MatchKings
After shortening the barrel from 30″ to 17″, total velocity reduction for the 250-grainers was 395 FPS, an average loss of 30.4 FPS per 1″ cut. The amount of velocity loss per inch rose as the barrel got shorter, with the biggest speed reduction, a loss of 55 FPS, coming with the cut from 18″ to 17″.

Start Velocity: 2942 FPS | End Velocity: 2547 FPS | Average Loss Per Inch: 30.4 FPS

.338 Lapua Magnum with 300gr Sierra MatchKings
Shooting the 300-grainers, total velocity reduction was 341 fps, an average of 26.2 FPS loss per 1″ cut (30″ down to 17″). However, the speed actually increased with the first cut from 30 inches to 29 inches. The tester noted: “The 300 SMK load showed a slight increase from 30″ to 29″. I’ve recorded this in other tests and it seems to be more common with a heavier load. I suspect it is primarily due to the small sample sizes being used along with the relative proximity of muzzle velocities in adjacent lengths.”

Start Velocity: 2833 FPS | End Velocity: 2492 FPS | Average Loss Per Inch: 26.2 FPS*

*Velocity rose with first cut. Velocities ranged from 2,871 FPS (29″) to 2,492 FPS (17″) for a total velocity loss of 341 FPS.

RifleShooter.com crunched the velocity numbers in some interesting ways. For example they analyzed rate of velocity loss, concluding that: “after the initial rate change, the rate of the change in velocity is fairly consistent.” (View Rate of Change Graph)

How Velocity Loss Alters Long-Range Ballistics
The testers wanted to determine how the velocity reductions “affect our ability to hit targets downrange”. So, Rifleshooter.com plotted changes in elevation and wind drift at all barrel lengths. This revealed something interesting — drift increased significantly below 26″ barrel length: “Above 26″ things look pretty good, below 22″ they change quickly.”

We highly recommend you read the whole story. Rifleshooter.com put in serious time and effort, resulting in solid, thought-provoking results. The data is presented in multiple tables and graphs, revealing inch-by-inch velocities, change “deltas”, and SDs at each length.

READ .338 LM Barrel Cut-down FULL TEST REPORT >>>

Permalink Bullets, Brass, Ammo, Gunsmithing, Tech Tip 4 Comments »
January 1st, 2017

6.5 Creedmoor — Velocity and Barrel Length — What to Expect

Rifleshooter.com 6.5 Creedmoor cut-down test

What do you get when you cut a 6.5 Creedmoor-chambered barrel down to just over 16 inches? A lot more velocity than you might think. Our friends at Rifleshooter.com recently did a barrel cut-down test with 6.5 Creedmoor test rifle, shortening the barrel from 27 to 16.1 inches in one-inch increments. Surprisingly, with a 142gr Sierra MK, the total velocity loss (as measured with a Magnetospeed) was just 158 FPS, an average of 14.4 FPS per inch of barrel length. With the lighter 120gr A-Max bullet, the total velocity loss was 233 FPS, or 21.8 FPS average loss per inch of barrel.

CLICK HERE to SEE All Velocity Values at All Barrel Lengths

To perform this velocity test, our friend Bill, Rifleshooter.com’s editor, built up a 6.5 Creedmoor rifle using a Remington Model 7 action, 1:8″ twist Green Mountain CM barrel, and MDT LSS Chassis, all obtained from Brownells.com.

Test Procedure
Five (5) rounds of each type of cartridge were fired at each barrel length and the velocity data was recorded with a MagnetoSpeed V3 barrel-mounted chronograph. The rifle was then cleared and the barrel was cut back one inch at a time from 27″ to just over 16″. NOTE: During this winter test, the air temperature was a very chilly 23° F. One would expect higher velocities across the board had the outside temperature been higher.

Read Full Story with All Test Results at Rifleshooter.com

The photo below shows how the barrel was cut down, inch-by-inch, using a rotary saw. The barrel was pre-scored at inch intervals. As the main purpose of the test was to measure velocity (not accuracy) the testers did not attempt to create perfect crowns.

Rifleshooter.com 6.5 Creedmoor cut-down test

6.5 Creedmoor vs. Other Mid-Sized 6.5mm Cartridges
The 6.5 Creedmoor is a very popular cartridge with the tactical and PRS crowd. This mid-size cartridge offers good ballistics, with less recoil than a .308 Winchester. There’s an excellent selection of 6.5mm bullets, and many powder choices for this cartridge. When compared to the very accurate 6.5×47 Lapua cartridge, the 6.5 Creedmoor offers similar performance with less expensive brass. For a tactical shooter who must sometimes leave brass on the ground, brass cost is a factor to consider. Here’s a selection of various 6.5 mm mid-sized cartridges. Left to right are: 6.5 Grendel, 6.5×47 Lapua, 6.5 Creedmoor with 120gr A-Max, 6.5 Creedmoor with 142gr Sierra MK, and .260 Remington.

6.5 Creedmoor Rifleshooter.com velocity barrel cut cut-down test saw blade

When asked to compare the 6.5 Creedmoor to the 6.5×47 Lapua, Rifleshooter.com’s editor stated: “If you don’t hand load, or are new to precision rifle shooting, get a 6.5 Creedmoor. If you shoot a lot, reload, have more disposable income, and like more esoteric cartridges, get a 6.5×47 Lapua. I am a big fan of the 6.5×47 Lapua. In my personal experience, the 6.5×47 Lapua seems to be slightly more accurate than the 6.5 Creedmoor. I attribute this to the quality of Lapua brass.”

Permalink Bullets, Brass, Ammo, Gunsmithing, Tactical 3 Comments »
December 2nd, 2016

Firearms Barrel Length and Overall Length — Know the Law

The Legal Brief is a feature of TheGuncollective.com that focuses on firearms rules and regulations. In this Legal Brief video, Attorney Adam Kraut explains key State and Federal regulations governing firearms, and explains how to ensure compliance with all applicable laws.

This five-minute video explains barrel length rules for rifles and shotguns, and also explains the best (and most fool-proof) methods to measure your barrel. In addition, the video explains how to measure firearm overall length. A rifle or shotgun which is less than 26 inches overall can also be classified as a “Short-barreled” rifle/shotgun subject to the NFA. NOTE: Under federal law “If the rifle or shotgun has a collapsible stock, the overall length is measured with the stock EXTENDED”.

short barrel barreled rifle shotgun NSA tax stamp ATF legal brief guncollective.com

Highlights of LEGAL BRIEF Discussion of Barrel Length and Firearm Overall Length

The ATF procedure to measure the length of a barrel is to measure from the closed bolt or breech face to the furthest end of the barrel or permanently attached muzzle device. ATF considers a muzzle device that has been permanently attached to be part of the barrel and therefore counts towards the length.

How to Measure Barrel Length: Drop [a] dowel or rod into the barrel until it touches the bolt or breech face, which has to be closed. Mark the outside of the rod at the end of the muzzle crown (if you don’t have a permanently attached muzzle device) or at the end of the muzzle device if it is permanently attached. Remove the rod and measure from the mark to the end of the rod. That is your barrel length[.]

Remember, if the barrel length is less than 16 inches, it is possible that the firearm could be a short barrel rifle (if you are building a rifle or it is already on a rifle) and if the barrel length is less than 18 inches, it is possible the firearm could be a short barrel shotgun (again if you are building a shotgun or it is already a shotgun). Both of these firearms would be subject to the purview of the National Firearms Act and would require the firearm to be registered accordingly.

How to Measure Overall Length:The overall length of your rifle or shotgun may also classify it as a Short Barrel Rifle or Short Barrel Shotgun. The overall length of a firearm is the distance between the muzzle of the barrel and the rearmost portion of the weapon measured on a line parallel to the axis of the bore. … If the rifle has a permanently attached muzzle device, that is part of the overall length. … If the rifle or shotgun has a collapsible stock, the overall length is measured with the stock extended.

READ FULL ARTICLE on Ammoland.com.

Links for this episode:

ATF Method for Measuring Barrel Length and Overall Length:
https://www.atf.gov/firearms/docs/atf-national-firearms-act-handbook-chapter-2/download
Firearm – 26 USC § 5845: https://www.law.cornell.edu/uscode/text/26/5845
Firearm – 27 CFR § 479.11: https://www.law.cornell.edu/cfr/text/27/479.11
Short Barrel Rifle – 18 USC § 921(a)(8): https://www.law.cornell.edu/uscode/text/18/921
Short Barrel Rifle – 27 CFR § 478.11: https://www.law.cornell.edu/cfr/text/27/478.11
Short Barrel Shotgun – 18 USC § 921(a)(6): https://www.law.cornell.edu/uscode/text/18/921
Short Barrel Shotgun – 27 CFR § 478.11: https://www.law.cornell.edu/cfr/text/27/478.11

Permalink - Articles, Gunsmithing 3 Comments »