I'm getting desperate!

[Fudmottin]

I'm trying to design an integral suppressor for the MKII series pistol. I do not want to give up the velocity that the AWC Amphibian does. But I still want reasonable suppression.

I really need to know what the normal pressure and velocity curves are in a 22LR barrel.

I want to be able to have a chance at working out the barrel length to stick with and where the ports should be so that I do not lose too much muzzle velocity and still keep the muzzle pressure down for suppression.

Please help.

Thanks.

[LouBoyd]

You couild get a box each of several brands of ammo, then use a "sacraficial" barrel and crhonograph a a few shots from each box as you cut down the barrel in increments. A used barrel for a T/C doesn't cost a lot. That would give some useful data.

Quickload could do that only if you know the characteristcs of each powder and bullet used in each brand. You could also Use an Oehler chamber strain gage rig to get the pressure/time curves. You'd still have to make a lot of shots on different ammo unless you've already chosen what you're going to use.

What's so important about not giving up any velocity? Isn't it to be subsonic? You may want to give up velocity depending on the ammo you use.

[remhunter]

awc gives up only a little in velocity so u can shoot standard high velocity subsonic (which saves a lot of $ when buying ammo). I own one and love it. If you do not make it subsonic then it will still be loud from the sonic crack of the bullet which kind of defeats the purpose unless all you are trying to do is shoot it comfortably without ear plugs. Which I do with .22 calibers anyway.

[Fudmottin]

I'm trying to find a middle ground where I get the choice of velocity of using a muzzle can but the handier short length of an integral (not to mention the visual appeal of an integral). I would like the bolt to cycle on Remington Subsonic which I have a fair bit of. I don't think there is any 40gr loads that will go super sonic in a 5 1/2 inch barrel anyway, although I could be wrong.

If all goes according to plan, I would have a pistol that is maybe an inch or two longer than the Amphibian, a little louder, and a flatter trajectory.

The barrel porting location is rather important to final results. The Amphibian starts way back at the chamber (just about) and has the barrel much shortened. I want to be closer to the muzzle end with a longer barrel. The ports want to vent into a chamber so that as the bullet reaches the muzzle, it is still under just enough pressure to overcome bearing friction.

The portion of the suppressor ahead of the muzzle would resemble a shortened version of a traditional can.

Also the suppressor will be threaded for takedown. The Amphibian is sealed. I don't know how long it takes to lead up. But it will happen eventually. I expect that the location and size of the ports keeps them from accumulating lead for a while though.

A final word on velocity. The ideal is near 1000 fps. This keeps you shy of the transonic range so that bullet flight noise doesn't become a problem. It also gives you somewhat more "point blank range" than 800 fps will which is about the best the Amphibian will do with fairly hot ammunition. Going lighter than 40 gr just makes things worse because you lose ballistic coefficient.

[Artful]

Originally Posted by Fudmottin

I'm trying to find a middle ground where I get the choice of velocity of using a muzzle can but the handier short length of an integral (not to mention the visual appeal of an integral). I would like the bolt to cycle on Remington Subsonic which I have a fair bit of. I don't think there is any 40gr loads that will go super sonic in a 5 1/2 inch barrel anyway, although I could be wrong.

All the 40 high velocity go supersonic in my 5.5 ruger barrel, All so far tested in 4.5 High Standard barrel stay subsonic. If your just shooting Rem. Subsonic of course it doesn't matter.

Quick google shows some Velocity vs barrel length
http://plainsmanscabin.yuku.com/topic/4050
_______________BARREL
FIREARM________LENGTH______VELOCITY______AMMUNITIO N
(MAKE)_________(INCHES)_____(FPS)________(BRAND)
(Model)___________________ CCI_____CCI______CCI
________________________STANDARD MINIMAG STINGER
S&W317____________3_____843______923________1,13 8
S&W 34____________4_____872______980________ 1,154
Kimber 1911_________5_____910_____1,037_______ 1,264
S&W K-22__________6______897_____1,023_______1,232
S&W 41____________7______959_____1,125_______1,422
Remington 504_____20_____1,100_____1,266_______1,576
Remington 12-C____24_____1,005_____1,150_______1,506
COPYRIGHT 2005 Publishers' Development Corporation

http://www.kifaruforums.net/archive/...hp/t-6867.html
In the VOL. 9, NO. 4 issue of GUNS & AMMO magazine, Bob Milek wrote an article titled: BARREL LENGTH VS VELOCITY, where he took a number of barrels and guns and cut down the barrels in one inch increments, measuring the velocity loss at each step of the process for a number of centerfires as well as the 22LRs. It's a very interesting article. Here are the velocities recorded for the 22LR starting at 14 inches and going down to 4 inches.

14" = 1,105 fps.
13" = 1,106
12" = 1,110
11" = 1,089
10" = 1,114
..9" = 1,077
..8" = 1,063
..7" = 1,057
..6" = 1,024
..5" = ..959
..4" = ..927 fps.

http://www.boards.ie/vbulletin/showt...php?p=59873169
We used five CZ 452 .22 rifles with different barrel lengths and fired six rounds each of six different cartridge types. The chart below reflects the average velocity of the six rounds.

The rifles were:
CZ 452 Ultra Lux with a 28.6” barrel
CZ 452 Special with a 24.8” barrel
CZ 452 American with a 22.5” barrel
CZ 452 FS with a 20.7” barrel
CZ 452 Classic with a 16.5” barrel (Fuzzy the Limey’s old CMP Sporter rifle)

The cartridges were:
CB Longs = CB
RWS Subsonic Hollow Points = SSHP
Wolf Match Target = Standard Velocity or SV
American Eagle Solids = Lead High Velocity or LHV
CCI Mini Mag Solids = Plated High Velocity or PHV
CCI Stingers = Hyper Velocity or HypVel

-----CB SSHP SV --LHV -PHV HypVel
28.6 652 968 1037 1206 1188 1660

24.8 676 997 1062 1219 1217 1660

22.5 653 998 1069 1229 1213 1708

20.7 701 957 1062 1224 1190 1661

16.5 685 949 1057 1205 1208 1666

The following information is from Mark White's book "The Ultimate Ruger 10/22 Manual and User's Guide" . Apparently, he cut a 28 inch barrel two inches at a time and measured for muzzle velocity.

Ruger 77/22; Remington Standard Velocity .22 LR ammunition
Barrel Length/ Velocity
28 1095
26 1107
24 1119
22 1129
20 1138
18 1149
16 1157
14 1149

[Rikky Lee]

Change the action springs.