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  #1  
Old 07-12-2018, 09:31 PM
John A.

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22 barrel length VS accuracy question



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Good evening guys.

I was hoping to ask a question from those more experienced than I am about barrel length and accuracy.

First, let me go into a few details about what I'm going to be doing when I get the paperwork back.

I intend to make an integrally suppressed bolt action 22lr.

I plan to use an old early lakefield (pre Savage) bolt action as the host rifle. It's been a good gun over the years and is pretty doggone accurate as it sits.

I will be shortening the barrel so that once I'm finished the added length of the suppressor plus barrel isn't unwieldy. I intend to keep the overall footprint at least the same or less than the 20 inch barrel that is on it now. So needless to say, the barrel is going to be shortened, recrowned and threaded regardless.

The hidden suppressor itself will be 6 inches long so that would put me cutting the barrel to at least somewhere between 10-14 inches.

The monocore baffle will be permanently pinned and welded to the barrel to make it longer than the minimum 16 inches so I don't have to double stamp the gun.

My questions that I am hoping to have answered is at what length barrel would I realistically expect the accuracy to start going downhill and taking a hit?

I know the Gemtech mist integral is using an 8 inch barrel, and most owners say it's marginal on accuracy out to 100 yards, but I'm wondering if I could realistically keep decent accuracy if I cut my barrel around 12 inches.

That would be a little shorter overall than it is now, and hopefully while maintaining enough accuracy to still hunt with.

From every chart that I have seen from folks that have done it before me says that 12 inches is about the magic number where 22lr doesn't really gain or lose any velocity from what the factories usually rate their 22 ammo velocity at, so I'm wondering if the 12" length is about where I want to be to maintain decent accuracy out to 100 yards or less.

Realistically I usually shoot 22's at 75 yards or less and more often less.

Thank you in advance for your time.
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Old 07-12-2018, 10:41 PM
octanejunkie

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Lots of articles and posts on this topic out there. What twist and what ammo are you planning on running?

Sent from my Pixel XL using Tapatalk
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  #3  
Old 07-12-2018, 11:02 PM
John A.

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I'll be perfectly honest, I don't know the twist rate.

It's an early 1968 gun and the barrel isn't marked with a twist rate.

With that said, it shoots 40 gr subs without a problem right now.

Shoots 36 gr HV without a problem too.

Never really tried anything else in it.

I've seen some really good info that essentially had the velocity from 20 inches all the way down to 1 inch.

Seems that 12 inches achieved the full velocity the bullets were rated at. So that's why I suspect that the 12 inch length would work as well as the 16" from a practical viewpoint. If it reaches full velocity at that point, I would suspect that there would be little to gain from the other 4 inches stability wise, other than the twist that you mentioned.

Here is the data that I'm basing it on:

----------------------------------------------

Barrel Length Remington High Velocity Winchester T22
4 in 1045 fps
8 1150
12 1220
16 1240
20 1235
24 1210
28 1170

From the same discussion some work down to a 1" barrel done by an RCMP lab:

"The chart is for Winchester HV while they say other brands were
included in the study and were the same for practical purposes.

len vel
1 606
2 820
3 940
4 1010
5 1049
6 1087
7 1115
8 1136
9 1158
10 1210
11 1200
12 1200
13 1200
14 1195
15 1205
16 1216
17 1216
18 1212
19 1199
20 1212
21 1237
22 1213

Super sonic at 7 inches, hope this helps."

Also this:
"These are from the book Silencer/History and Performance by Allen c. Paulson.
Using a new Ruger 10/22 bbl. and cutting off 2" at a time.
Ammo was Winchester Wildcat 22lr. at 60deg.f"

18.5" = 1,229
16.0" = 1,226
14.0" = 1,212
12.0" = 1,197
10.0" = 1,175
8.0" = 1,152
6.0" = 1,088
4.0" = 1,004
2.0" = 794
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  #4  
Old 07-13-2018, 08:41 PM
samven
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So these velocities and barrel length are going to be very dependent on the bullet weight, the powder used, the chamber dimensions and the powder temp. 16" is considered to be the safe length for a full burn with the majority of ammo. If max velocity is important I would stay as close to 16 as possible but if accuracy is your thing you need to find the tightest spot in the bore and cut there no matter what the length ends up at. My second biggest concern would be the threading and the welding. These have to be done by someone who really really knows his business. Hitting an old Rimfire (mild) steel barrel with that kind of heat after cutting it could set up some crazy stresses. I would lean towards some of the modern epoxies. Some are so strong now that it would require destruction of the unit to remove and that should satisfy ATF.
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Old 07-13-2018, 08:55 PM
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Quote:
Originally Posted by John A. View Post
My questions that I am hoping to have answered is at what length barrel would I realistically expect the accuracy to start going downhill and taking a hit?
Accuracy is not dependant on any particular barrel length.
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Old 07-13-2018, 09:27 PM
John A.

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Thanks for the replies gentlemen. I do appreciate them.

The bore is around .203 'ish at the muzzle now IIRC so anywhere making up the bore should be similar throughout if not a little tighter due to erosion at the bore. It's far from being shot out despite its' age.

As for cutting and threading, I tend to run coolant which prolongs tool life and isn't so hard on what you're cutting.

While I would like to use an adhesive, that doesn't meet what atf says they accept for permanent attachment. Though we both agree that there are some that would take a lot to get loose.

To keep temps as cool as possible, I was going to drill through the monocore stack and the barrel, insert a pin through both and tig weld over each side where the pin protrudes out of the monocore thread which is larger diameter than the barrel itself. That is the least stressful methods that I know of to impart on the barrel. And is atf approved.


IHMSA80x80 I can see a lot of truth in your reply. I guess that I should've said the gun shoots well now and I don't want to kill the accuracy by going too short. That's why those 3.5" P22's aren't known for their world famous precision.
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Old 07-14-2018, 12:45 PM
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Accuracy is dependant on the quality of the barrel, chamber design, the gunsmithing to build that barrel, whether factory or custom, lapping of the barrel, crown and the ammo used.

If those P22's aren't accurate, it isn't because of the length.
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Old 07-14-2018, 01:52 PM
John A.

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While I won't necessarily disagree with what you've wrote, I have noticed not many people using browning buckmarks and ruger Mk 4's for long range shooting accuracy either.

Otherwise, there would be little need to have a 22 rifle.

And why snub nose revolvers aren't used in Olympic competitions either I guess.
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Old 07-14-2018, 02:59 PM
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FWIW, I have an Anschutz with an 18" barrel (factory threaded for suppressor) and a Remington 40X with a 28" barrel. They are both superbly accurate when fed the ammo they like.
Chris
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Old 07-14-2018, 08:36 PM
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Quote:
Originally Posted by John A. View Post
While I won't necessarily disagree with what you've wrote, I have noticed not many people using browning buckmarks and ruger Mk 4's for long range shooting accuracy either.

If it's accurate, you could use it. I use my Buckmark Silhouette out to 200 meters.

Otherwise, there would be little need to have a 22 rifle.

Rifles are much easier to shoot well than pistols are.

And why snub nose revolvers aren't used in Olympic competitions either I guess.
It's not because of barrel length. Sight radius is a big issue. Snub nose revolvers don't really have much.
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Old 07-14-2018, 08:37 PM
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Quote:
Originally Posted by NCchris View Post
FWIW, I have an Anschutz with an 18" barrel (factory threaded for suppressor) and a Remington 40X with a 28" barrel. They are both superbly accurate when fed the ammo they like.
Chris
I have several Exemplars with 10, 12 and 15" barrels that are also superbly accurate. They regularly outshoot the rifle guys here.
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Old 07-14-2018, 09:21 PM
John A.

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Is one of the 3 inherently more accurate than the others? That's what I'm asking, are any of the 3 accurate enough to hunt small game with at 75 yards as less?
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Old 07-15-2018, 06:39 AM
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Length doesn't matter

There are many variables to an individual barrel that do matter.

First, no barrel is perfectly straight.

Second no bore is perfectly concentric or straight.

Third the metallurgy and rifling varies throughout the barrel and among barrels.

Add a 20,000 PSI explosion at one end affected by ignition and minute chamber differences.

You cannot even assume all barrels of a certain brand and length shoot the same. That would be as silly as assuming all rifles within a model line shoot the same, which we know is not true.

These differences are why no conclusive statements can be made about any barrel. No two are the same, or vibrate the same. Few quarterbacks could throw a "spiral" like Dan Marino, and a similar analogy can be made for barrels.

While these differences are tiny, they manifest themselves significantly with distance.

This is why there are some $200 Savages that out-shoot some $2000 Anschutz rifles. I have seen new Anschutzs and Coopers that needed to be rebarreled.

If I had to pick an "inherent" difference that matters, it would be a heavy barrel that may not oscillate as widely. Tony Kidd has stated this regarding barrel diameter. However that is only one criteria of several. I have seen many pencil barrels outshoot heavy barrels.

Small game at 75 yards should not be a problem with any barrel. There's only one way to find out, and unfortunately assuming is not it...Tom

Last edited by Thomasconnor; 07-15-2018 at 07:05 AM.
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Old 07-15-2018, 09:08 AM
John A.

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OK, I guess I get it now from the various replies I have gotten.

There is too much voodoo involved to be able to say without having a witch doctors license.

As I said before, the gun shoots reasonably accurate at 0-75 yards now. So I made the assumption the barrel wouldn't change chemical makeup after I cut the barrel.

I was mainly asking if 12 inches is probably long enough to likely stabilize the same bullet weights that it shoots well now with.

While barrel harmonics changing with the shortened barrel may produce a slight shift in POI, I believe that it would be within a few click clicks on the scope at worst.

Also, by shortening the barrel should actually create a stiffer barrel in the end.

What happens if you have a 1 inch diameter piece of PVC water pipe that is 10 foot long when you carry it?

It makes a long rainbow shape and bounces wildly up and down each step you take.

What happens if you only have a 10 inch long piece of that same pvc pipe and carry it? It doesn't bend and bounce as much as you carry it does it?

I guess my question should have been:
"Has anyone shortened their 20 inch barrels to 12-14 inches? If so, could you still hit what you usually aim at?
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Old 07-15-2018, 09:12 AM
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Quote:
Originally Posted by John A. View Post
I'm wondering if I could realistically keep decent accuracy if I cut my barrel around 12 inches.
I read all the powder is most utilized, burnt, by a 16" barrel. I don't remember how much pressure, muzzle velocity, would be sacrificed by reducing it to 12". Somewhere there's a published experiment where they tested cutting down a barrel by, 2"?, increments.
IMA you might try slugging the barrel before cutting.
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