What's up with my velocity?

dave_t73

dave_t73

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Ok guys, this has been puzzling me for some time now. I have a Mossberg .22 semi auto with an 18.5" barrel. I've been testing out various rounds lately and out of curiosity, started recording some velocities using my Chrony.

All my velocities seem to be consistently below normal by about 150-200fps. Here's what I've measured so far on average (test vs Manufacturers claim):

-Velocitor: Mfc = 1450 Test = 1255
-Stingers: Mfc = 1600 Test = 1450
-Green Tag: Mfc = 1000 Test = 900
- CB's: Mfc = 720 Test = 510

The readings above were averaged over 15 shots. I can't recall the exact Mfc velocities so I'm estimating.

Could the difference be due to CCI lying about performance? I once thought it was because of the cold weather (I shot on 2 different days,
T = -5C) but that doesn't make sense to me.

Any gumshoes out there have any ideas:confused:
 
You would have to find out the exact test rig they use and duplicate it. Barrel length, action type (semi vs single) and ambient conditions all make a difference.

(E) :cool:
 
Barrel dimensions and action have a lot to do with it. Some of the gas that is used to push the bullet out the barrel are also used to cycle your semi-auto.
Therefore, a bolt gun will give higher velocities then a semi with the same ammo and barrel length.
 
I've chrony'd Stingers out of my 10/22 (also an 18 1/2" barrel) and got almost exactly 1600 fps from the ones that I tested. For what ever reasons some barrels seem a bit slow. I have a Tikka T-3 that has a "slow" barrel.... usually the velocity that I get from it appears to be 100 - 150 fps less than what I've been expecting according to the reloading information that I've looked at. Maybe your Mossberg is like this as well?
 
These are summer velocities.
I tried chronying in cold weather and got lower numbers, just as you would expect. I'll try to find the cold weather figures.

Lapua Super Club
924 962 962 986 956 994

Eley
986 989 1001 1006 1021

Dynapoints
952 1078 1085 1082 1060 1109

Rem Target
1074 1125 1013 1022

T22
1107 1113 1119 1104 1120 1113 1106

Fed Classic HV
1212 1203 1181 1169 1205

Green Tag
957 971 949 966 959

Blaser
1220 1199 1207 1190 1201 1190 1212 1194 1218

Win Wildcat
1118 1165 1151 1166 1197 1173 1186

Win HV HP
1129 1111 1120 1125 1138 1132

PMC Target
1028 1008 1014 1025

CCI 17
2458 2413

Horn 17
2555 2531

Rem 17
2555 2548
 
Also any oil left in the barrel will effect velocity also.

I always run a few dry patches through before I shoot, and after a few hundred rounds while I'm still at the range, and I have noticed a difference.

And yes cold weather is a big factor.

What type of Mossberg do you have?
 
Its a Mossberg "New Haven" Model 251C Nothing special at all. In fact, it doesn't even shoot that well, but it hold 14rds in the tube mag and is pretty fun to shoot.

I noticed the velocitors were the most consistent round (varying only 25 fps over 15 shots) and the Stingers were the least consistent (varying up to 130 fps)
 
Calum said:
Also any oil left in the barrel will effect velocity also.

I always run a few dry patches through before I shoot, and after a few hundred rounds while I'm still at the range, and I have noticed a difference.
Click to expand...

Why would you clean it? I know some competitive smallbore shooters that might clean the barrel every 1000 rounds. If it is still shooting well, they leave it until the groups open up. Once you clean it you fire 10 round or so just to foul the barrel, so it will shoot tight groups again:confused:
 
maynard said:
Why would you clean it? I know some competitive smallbore shooters that might clean the barrel every 1000 rounds. If it is still shooting well, they leave it until the groups open up. Once you clean it you fire 10 round or so just to foul the barrel, so it will shoot tight groups again:confused:
Click to expand...

Depends on how dirty the ammo you feed it is, and even then it seems to be different from one lot number to another, and from one rifle to another even in the same model type.

Also everyone has a different method/definition of cleaning and storage, so a few dry patches down the pipe can't hurt IMHO. :D
 
Found my cold weather numbers.
@ -3ºC
Lapua 977 933 935 937
Blazer 1134 1182
T22 1037 1022

Warm weather
Lapua Super Club 924 962 962 986 956 994
Blaser 1220 1199 1207 1190 1201 1190 1212 1194 1218
T22 1107 1113 1119 1104 1120 1113 1106

Looks like about a 5% reduction in speed.
 
bisonhd said:
16" barrel is about optimum for 22 LR cartridge for max. velocity.
Click to expand...

Is that all? So just about every .22 barrel out there is too long by 4" to 8"? Not necessarily doubting you (coughyescough) ;) but do you have any backup info for this? This way I can better manage which rifle to take along for different tasks.
 
Grouse Man said:
Is that all? So just about every .22 barrel out there is too long by 4" to 8"? Not necessarily doubting you (coughyescough) ;) but do you have any backup info for this? This way I can better manage which rifle to take along for different tasks.
Click to expand...


Coughyescough is right!
It has been proven that Most of the powder in a rimfire cartridge burns in the first 16" of the barrel. Most rimfire data will show optimal muzzle velocity with a 16" barrel... that is fact.

On the plus side, a longer barrel will favor a shooter using iron sights.
 
Goose25 said:
It has been proven that Most of the powder in a rimfire cartridge burns in the first 16" of the barrel. Most rimfire data will show optimal muzzle velocity with a 16" barrel... that is fact.

On the plus side, a longer barrel will favor a shooter using iron sights.
Click to expand...


I haven't seen this 'most rimfire data' that you're referring to, but powder burned up may not necessarily mean max velocity. Even after the powder is completely burned, the gas pressure is still exerting force on the bullet and accelerating it. Thoughts?

I'll look through the Federal site and see if there's any references there . . .
 
I will have to agree with Goose25 here. Anschutz shortened the barrels on some models. Testing proved the extra barrel time did nothing for accuracy after 16 inches and in fact may have been less accurate do to shooter error.
To keep the same or longer sight radius a bloop tube was introduced.
Of course not all shooters wanted shorter barrels and felt the longer barrels were better for 100 yard shooting. That is why you can get Anschutz in long or short barrels.
 
I am well aware of the 16" listed optimum barrel length for a 22 rimfire. I do believe that this was the length given for standard velocity long rifle ammo. Slightly longer barrels gave max velocity with HV stuff and stingers, etc. However, I like the longer barrels for the noise reduction they afford. I have an old SS Winchester [M68, 27" tube] that shoots standard velocity LR ammo quietly, and subsonic offerings are practically silent.
 
Grouse Man said:
I haven't seen this 'most rimfire data' that you're referring to, but powder burned up may not necessarily mean max velocity. Even after the powder is completely burned, the gas pressure is still exerting force on the bullet and accelerating it. Thoughts?

I'll look through the Federal site and see if there's any references there . . .
Click to expand...



Never doubt what I say.... My mind knows all (**cough**cough**):D :D :D
 
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