.223 Velocities in a 16" AR: What should I be looking for???

[GunAdmirer]

What velocity should I be looking for with factory 55 FMJ BT .223 ammo out of my 16" barrel Bushmaster (WWB, UMC, Fed Eagle)?

On their website, Bushmaster says 3,100 fps out of a 16" barrel. However, they do not specify if the ammo is civilian factory or military specification.

My handloads have come out to around 2,900 fps so far. Most factory ammo and reloading manual velocity data is based on 20-22" barrels. I'd like to know if I'm close to where I need to be or if I should keep developing my load.

 

[Lennyjoe]

What kind of loads are you running?

I'm getting 3000fps out of my Oly 16" with 25.0gr of H-335 and CCI mag primers under 55gr fmj's.

Just made some 25.6gr loads and will run them thru the chrono soonest.

 

[ribbonstone]

Some manuals list loads for the T/C 16" handgun barels....16" is the key here as the bullet won't know if there is a buttstock back there or not.

 

[AFhack]

What kind of groups are you getting?

Load development for a particular rifle isn'at all about muzzle velocity. Within a particular range you might find your rifle grouping better 200-300 fps below (or above) what some manuals post as "optimums."

 

[dmftoy1]

I see about 3200 out of my 16 bushie for LC XM193 ammo, but my homemade 55 FMJ (H335) seems to run about 2850-2940 with 24-24.6 grains. (FWIW) I tend to load pretty conservatively as I don't want to blow anything up.

Regards,
Dave

 

[ocabj]

XM193 pushes at around 3150-3200fps out of my 16" Colt Sporter barrel.

3200 is about normal for military M193 and a 16" barrel. This is hotter than commercial .223 Remington ammunition and exceeds SAAMI specifications for .223 Rem.

If you try to handload to match M193 (or any military load), you're most likely going to go over the maximum listed charge weight in the reloading manuals for that specific powder. There's nothing wrong with this. As long as you are loading for an AR you should be ok. Be sure to work up carefully.

 

[GunAdmirer]

I took matters in my own hands this afternoon.

UMC 55 gr. 2,881 avg fps - a few rounds were quite a bit higher at the end of the test (2,936)

Lake City 55 gr. 3,116

25.1 gr. H335 55 gr. 2,943

WWB 55 gr. 2,980 (tested later in the day)

Federal 55 gr 2,978 (not enough rounds fired)

This data is not reliable enough to base any real conclusions on. I will have to put together a better test, but it is interesting. At least I know my handloads are in the neighborhood of factory rounds.

Temp 85 degrees - 2:30 p.m. - sunny day
Chrony F1 - 15ft

It appears that temperature has a big effect on velocity. The data I got today was significantly higher than on a cooler day earlier this week.

I think I will stick with 25.0 grains of H335 for my handloads.
Bushmaster M4 16" barrel

 

[Lennyjoe]

I've found that the H-335 likes CCI mag primers best.

 

[GunAdmirer]

I got out and chronographed more loads this afternoon. The conditions were similar to and the results consistent with my previous session.

Here's some more unscientific results:

UMC factory 55 gr. 2,917 avg fps

Handload 25.0 gr. H335 55 gr. FMJ 2,923

Handload 25.3 gr. H335 55 gr. FMJ 2,992 (another string was 2,973)
(handloads used CCI 41 Arsenal primers (magnum))

WWB factory 55 gr. FMJ 2,982

Again, this data is not reliable enough to base any real conclusions on. It appears that it takes 25.3 grains of H335 to get the equivalent velocity of WWB factory ammo (which was my primary goal).

Temp 85-90 degrees - 1:30 p.m. - sunny day
Chrony F1 - 15ft
NEW Bushmaster M4 16" barrel - 120 rounds with complete reliability so far.

Disclaimer:
Don't take my word for it! I hope this information helps someone, but you must work up your own loads. You must verify the data for yourself.

 

[Clark]

I have seen Malasian 55 gr surplus ammo get 3300 fps with 14" of barrel.
That ammo is HOT!

 

[tom32]

I have pulled LC XM193 ammo and stuffed Hornady 55 gr vmax moly bullets in them with success. They run about 3080 fps from a 16" barrel and pressure signs on the case and primer are less than with the standard M193 loads. Accuracy is also much better than with the 55 fmjbt. I has some Hirtenberger that ran over 3100 fps from a 16" barrel, those were the days.

 

[ball3006]

I never worry about what the velocity...

is. I work up a load that is the most accurate and leave it at that.........chris3