Reloads and reliability??

[turnburglar]

Just thought I would post with some more experience:

I've loaded about 1.5k in 556 at this point and had to mortar my gun twice. Not anything to be overly concerned about, but thought I would get the forums opinion. What could be causing this?

Also the two recipes I have settled on is:

25gr H335 under a 62gr FMJ. Seems mild. I could probably work up to 26grs.

24.3 gr H335 under 77gr SMK. This is hot. Cant work up any hotter without flattening primers. This load has performed well for me. Used it in a match and got good hits on the 500 - 720 yard targets.

I still need to test these loads when it gets 115*F. Has anyone had any experience with a load not working out in the heat before?

[ViniVidivici]

I use 24.4 with 62gr FMJ with excellent results. I wouldn't go to 26, as the Hornady data I have for 5.56NATO shows 25.4 as max, and for .223 shows 22.9 as max.

I use 22.0gr behind a 75gr OTM bullet. I would think your 77gr load is hot as hell.

Me, I have not seen noticeable effects in hot vs. cold with H335.

As to having to mortar the gun open, it sounds like you're not getting a good full-length resize. I've seen that with worn dies and chambers that're on the tight end.

Your chamber 5.56, .223, or .223Wylde?

I suppose it's also possible that if loads are too high pressure, they could expand the case so that they're that much harder to extract.

[sinister]

If you're using range pick-up brass and have different chambers (tight commercial or match chambers all the way to loosey-goosey 5.56mm mil chambers) you might try an RCBS Small Base sizing die. It will size your brass closer to factory dimensions to cycle in most guns (especially lower on the body around 1/4-inch from the base of the case), rather than just minimally.

I'm assuming you are trimming your cases to length.

[AndyLate]

I have not reloaded a lot more 5.56/.223 than you, maybe 2-3000 rounds (I don't keep track). The only 5.56 reloads I have ever had an issue with were a batch that I loaded way over max length (I do not remember how I pulled that boneheaded move). They worked fine from GI mags, but drug inside PMAGS.

I tend to load comfortably shy of max, especially for general purpose loads. If you are just under loads that flatten primers now, they will be overpressure in 115 degree weather.

Andy

[turnburglar]

Just too answer a few questions:

Both times I had to mortar a round; it was an unfired round. Usually to unload and show clear.

Each time was from a different barrel. One BCM 16 ELW, and one BRT MPR16. Both I believe have 556 chambers.

My brass is just random range pick ups.

I trim with a WFT trimmer to 1.750"

I size with a Lee full length sizing die, but I have had set up issues in the past; and will pay more attention to perfection next time I set up and size a bunch of brass.

[AndyLate]

Just too answer a few questions:

Both times I had to mortar a round; it was an unfired round. Usually to unload and show clear.

Each time was from a different barrel. One BCM 16 ELW, and one BRT MPR16. Both I believe have 556 chambers.

My brass is just random range pick ups.

I trim with a WFT trimmer to 1.750"

I size with a Lee full length sizing die, but I have had set up issues in the past; and will pay more attention to perfection next time I set up and size a bunch of brass.

Honestly, VVV and Sinister pretty much answered it. Either size a bit more or use the small base die.

It makes sense that you have to mortar the unfired reloads when the case is not sized enough.

Andy

[ViniVidivici]

Yes, you are definitely not getting them to resize sufficiently.

[markm]

A case gauge is your answer. Years ago I sized some brass a C hair over the max shelf, and got the same sticking problem.

[sinister]

A case gauge is your answer. Years ago I sized some brass a C hair over the max shelf, and got the same sticking problem.

JP and Sheridan case gages will check to verify your cases are sized correctly to chamber and extract-eject. Most others (including Dillon and Wilson) only verify whether the case shoulder has been set back enough and if they're above-below minimum and maximum length.

[turnburglar]

Awesome thanks for the reply's.

Im gonna go through my process and re set up my dies and try and get this sizing issue figured out.

I thought it was weird that I never had an issue with the gun cycling but had to mortar some (2) un fired reloads. Sizing makes total sense.