Home Forums Hunting & Shooting AR and Tactical Rifles 556 + 62 grain M855

This is more of a reloading question but I'm putting it here for the larger AR audience. If anyone has quickload I could use a favor.

556 LC brass + 62 gr M855 bullets + H335 + CCI small rifle mag primers.

Can I get to 2900 fps with those components and what pressure would it be at?

I've looked at a couple "free" calculators online, and, yeah, I dunno if they're telling me the truth.

Thanks to anyone who can run those numbers for me, looking to see if powder on hand will work.

Hodgdon H335 this is 223 data.



2.260" 19.3 starting load 2,678 47,500 PSI 21.4 grains max and 2,887 from a 24 inch barrel at 53,600 PSI

If your getting 2900 from a 16 inch barrel thats pretty sporty.

Out of a 20" barrel with a 5.56 chamber, yes, you can get 2900, but you'll be a lot hotter than 54K PSI.

I didn't stutter in my OP.......

Already have the Hodgdon data, and I'm not asking about 223.

Factory M855 green tip runs 2940 average out of my 556 chambered 16" AR, clocked with a Garmin. I've sourced that exact bullet and wondering if I can safely duplicate that speed WITH H335, or not. I'm seeing indications yes, but want to know what quickload has to say.

Considering the factor powder is H335 (technically it's wc844 but the same difference) I'd see why you couldn't.

Mil-spec is 28.5gr behind the 55gr bullets. I don't recall the Mil-spec loading for the 62's off the top of my head.

If I remember right it's 26.1 grains of wc844 (NATO spec), generically, depending on the lot they're testing.

I just have a boatload of H335 and would like to use it instead of buying something else. About 3K of LC brass to load up.

Just go to max load and start increasing your load a couple grains at a time until you see pressure signs? How hard can this be?

Well, that's the plan, but it's nice to see some parameters to go by.

No??

I have a long time friend who uses 24.5 grains of H335 with a 62 grain FMJ out of his 16" Smith and Wesson AR. He claims it's accurate but does not know the velocity. If you aren't seeing signs of pressure at 24.5 that load sounds reasonable. Only a chrono will tell you the truth about velocity.

kwg

FA, how long is your barrel?

I tried to reload Quick Load tonight, but my old version won't work with my new operating system.

Sorry, can't help you there.

Yes you can. You'll be at 60k+psi. People do it.

But I hate to be a wet blanket - why? The M855 is a relatively [bleep] bullet and unless you have a need to penetrate a helmet at 400 meters, I wouldn't waste the powder and primer. But that's just me

Same issue here. Oh well.

Can you recrimp your primers?

Because I want to, but that's just me.....

Seriously though, 15 cents per bullet is pretty cheap shooting these days. Pre-price increase craziness powder and primer stock, no worries on my end.

Primers may back out at that level.

Duly noted.....

No. I don't see primers backing out until you are well over 60K. At least never did for us.

Last thing I would believe is quick load.

Load up in increments and see what happens. while the difference in 100 fps is really overall negligible unless you have to have the the least bit of wind drift possible... and since you are shooting ball 62 thats evidently not a factor, if you can get up to 2900 give or take its all good.

Couple things IF I had the desire... coated bullets. N500 series powders. Yup I know you have 335. And odd groove barrels.

Assuming you have the correct gas port size I stop pressure wise when I start getting ejector marks. Faint ones now and then are likely variable case volume issues but you are at the top end. But constant and heavy marks are more than I want. Verification of gas port issues comes to me somewhat by rim lifts. If the extractor is lifting the rim and you are getting ejector marks then you are ported to big likely. Get rid of the rim lifts or dont' have em but have heavy ejector marks then you would be on the top side of my comfort range and back off about half a grain IMHO.

For those that just have to.... you can make a primer crimping tool. They may even sell commercially these days. Loctite does not keep primers in. Long story of a guy that just had to have the last 50 FPS or so...

Thanks Rost.

I'm just looking to match up with the factory M855 already on hand. Can't see why I couldn't in the same brass with the same bullet.

Seeing how primer type isnt a factor in predictive software, 62 grain fmj, case capacity 31 grains, 26.5 grains 335 ~2890 from 16” barrel @ 59,000 psi.