# Thread: .22 Win. Mag. peak velocity @ what barrel length....?

1. ## .22 Win. Mag. peak velocity @ what barrel length....?

What is the barrel length beyond which the .22 Winchester Magnum fails to gain velocity? I am thinking it is around 14". Yes it could vary a bit depending on bullet weight. I am going to shorten a 21" barrel to 16.062" however if peak velocity is at 17.3" I'll stop there.

2. Wow, I was hoping to fire up the Hacksaw tomorrow.

3. I don’t know the answer to your question, but I'll try to help.
I have heard and read in the attached articles by Hawks and Kelly, that you will lose between 300-500 fps going from a 22 mag rifle to hand gun.
If you can get 1333 fps in a four inch barrel, and 1442 in a six, then there is approximately a 50 fps gain per inch. So if the bullet maintained that acceleration up to the 1903 to 2000 max fps of a rifle barrel, it would take 16” of barrel to gain the 500 fps to get into the 1900-2000 range. I do not have the actual formula for calculating that theory, but would expect it to be close. My logic is probably incorrect.

Anyhow the campfire article I found argues your 21 inch barrel is about perfect.

Personally, I think I’d stay with the 21, or at the most drop down to 18.

“With most magnum handgun cartridges, there is about a 300-400 fps velocity drop as compared to the same round fired from a rifle, and the .22 Magnum is no exception. Winchester's 40-grain Hollowpoint gives 1903 from my 24-inch CZ rifle; the same ammo from my six-inch AMT clocks 1442 fps, and the four-inch AMT gives 1333 fps.” (Kelly)

“The new bullet weighed 40 grains, the same as the .22 LR bullet, but it was a true jacketed bullet, available in jacketed hollow point (JHP) and full metal jacket (FMJ) forms. .22 WMR bullets are generally of flat point or round nose shape, although Remington offers a Pointed Soft Point bullet. The original catalog muzzle velocity (MV) from a rifle barrel was 2000 fps, or 1550 fps from a pistol barrel. RWS still advertises a 40 grain bullet at a MV of 2020 fps and ME of 360 ft. lbs.” (Hawks)

http://www.gunblast.com/Paco_22AutoMag.htm

http://www.chuckhawks.com/compared_17HMR_22WMR.htm

http://www.tacticaloperations.com/SWATbarrel/

4. You could follow the SWAT articles idea and cut one inch off at a time and test your velocity. It would take longer, cutting/crowning/testing, but you would have measurable results by the inch.

5. Thank you, The research has been done back in the 70's and is in a book about .22 Rim fires. And they clock several loads as they cut 1" off the barrel. Sadly My copy is in buried storage in a warehouse in Los Anchorage. I was hoping someone else owned that book.

6. Yeah, I have seen different articles over the years, but don't have anything handy over here other than the internet.

Good luck with the project and if you would, post some results once you are done.

Thanks,
Ralph

7. Yes, It is a Remington M-597 .22 Win Mag. with Heavy Barrel & Laminated Stock. Thinking it would make a cute "Winter" Walk'about firearm....

8. Sounds nice. I don't have any experience with the Remington M597, but just went to their website and looked at it.

Seems like pretty versital set up. I like the collapsible stocks they offer, seems like with a shorter barrel like you are thinking that would be a nice pack rifle.

Now I'm very interested in the outcome of your project.

How long have you had your rifle, and have you had any problems with it? Any feeding or cycling issues? How is the accuracy?

Thanks

9. Not exactly what you are looking for, but there was a little study on the 22 long rifle in an old NRA Rifleman Mag. I think it was from the 60's, I know the UAF library had a copy because that is where I read it.

Basically they took a 44 caliber single shot and lined it with 22 long rifle barrel the then tested about 5 different types of ammunition. Then cut off and inch and repeated. They then ploted up the results with barrel length on the horizontal and velocity on the vertical axis. The results were roughly parabolic in shape. I do not remember the details but I do remember that the velocity over a number of barrel lengths near the ideal was relatively unchanged. Also there was a lot of variation between types of ammunition. One in particular (I think they where stingers) really like a much longer barrel then the others. If memory serves the ideal for most ammunition was about 12 to 14 inches.

I would suspect that the 22 WMR would like an even longer barrel then this as it burns more and slower powder.

10. Briefly, from my little NRA Fact Book…...

22 LR probably gets max velocity from 18.5” barrel.

Results vary, from barrel to barrel, ammo to ammo.

22 LR High-Speed loads 1467 fps, in 18.5” barrel, and 1338 fps in 25" nch barrel.

This anomaly is because 22 cal. barrels are long in proportion to their bore.

I suspect that a 22 Mag. would require a slightly longer barrel than a 22 LR, given, it has greater case capacity, and perhaps uses a slower powder.

Smitty of the North

11. Originally Posted by Smitty of the North
Briefly, from my little NRA Fact Book…...

22 LR probably gets max velocity from 18.5” barrel.

Results vary, from barrel to barrel, ammo to ammo.

22 LR High-Speed loads 1467 fps, in 18.5” barrel, and 1338 fps in 25" nch barrel.

This anomaly is because 22 cal. barrels are long in proportion to their bore.

I suspect that a 22 Mag. would require a slightly longer barrel than a 22 LR, given, it has greater case capacity, and perhaps uses a slower powder.

Smitty of the North
Years ago I put them both over a crono from my 7-3/4” Ruger Single Six that has both cylinders and the 22lr was about 50fps faster than the mag. From my rifles, two different rifles of course, the mag was something like 150fps faster. My un-scientific conclusion was the mag is a rifle round and a waste of money to shoot from the short barrel of my Ruger sixgun. I suspect that if you cut shorter than 18” you would be ahead to get a 22lr as the mag is likely clocking the same speed at a lot more money per round.

12. ## It's an interesting cartridge, but you gotta be realistic about it.

Years ago I put them both over a crono from my 7-3/4” Ruger Single Six that has both cylinders and the 22lr was about 50fps faster than the mag. From my rifles, two different rifles of course, the mag was something like 150fps faster. My un-scientific conclusion was the mag is a rifle round and a waste of money to shoot from the short barrel of my Ruger sixgun. I suspect that if you cut shorter than 18” you would be ahead to get a 22lr as the mag is likely clocking the same speed at a lot more money per round.

I never heard of a 7-3/4" barreled Ruger Single Six. I thought the longest barrels were 6.5" and the buntline at 9 inches.

That's amazing. I would have thought that, in a revolver with a 6.5" barrel the velocity would be ahead of the 22 LR. I do know the muzzle flash at night is probably double that of a 22 LR. A lot of powder burns outside the barrel, I guess.

Firing a 22 Mag. in a short barreled handgun, without ear protection would be murder to the ears, I'm sure.

My Single Six is 22 LR only. I got it before the convertibles came out. They would sell you an extry cylinder if you had a 22 Mag. but not if you had a 22 LR.

As I remember from reading in the American Rifleman, when that magazine was far more useful than it is today, the barrel for the 22 Mag. has a slightly larger bore, and the cartridge has a slightly larger diameter bullet, and it was heavier plated. The softer 22 LR bullet worked well in the Mag. barrel.

Currently, I have a rifle chambered for 22 Mag. I'm glad I don't have a 22 Mag. handgun. After checking out what you've said, (huge velocity loss) I've concluded that it's of no real advantage, in a handgun, but some disadvantages.

Smitty of the North

13. Today I cut the barrel to 16.4" HOWEVER I found that I have a flash suppressor that came off a 6.8SPC and the Outside Diameter of Barrel and suppressor are same. So if I could get concrete data on minimum Barrel length to get near full velocity, I would consider going shorter and having the suppressor brazed on.

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