unexplained high velocity with H335 and damage.

bakerboy

bakerboy

New member
This has me stumped. Blew up my AR with 24 gr of H335 and a 69 gr Sierra. Their data said 23.8 max. Ok my fault. I thought I had worked up to this load but maybe the much larger bearing surface of this bullet fooled me. Still a basically max book load blows up a gun???? Please note: I only have H335 so it wasn't a powder mixup. I pulled all the remaining bullets and reweighed the powder. 23.8 so no weighing problem. I always check my balance beam with a bullet, so that is not the problem. So I reload the Sierras 69 gr ( .2235 per my mic.) So it's not the wrong bullet. Using 22 gr of H335.(scale again verified with bullet). Now get this, 22 gr is below the minimum of 23 gr which is listed as 2700 fps. My 22 gr loads popped the primers. I didn't know on the first but the second didn't eject and when I pulled it the primer fell out so I immediately stopped. I checked the chrony. 3100 fps. This is not possible. The first bullet was a bullseye and the second never even hit the target. I found a flattened jacket stuck in the plywood below the target. My Krieger barrel looks ok to me. This is some crazy stuff happening. I only know to pull about 50 rounds and start over with different powder unless my barrel is causing this which I don't understand at all. HELP!!!!
 
Before I found out that 335 was temperature sensitive I had the same problem. Had loaded some rounds for AR ( a grain or so below max) in the winter and shot fine. Same load in the heat of summer around 90-95 degrees well lets just say I had to replace a few parts in the AR plus dig some out of my arm. I don't use 335 any more.
 
looks like my h335 will be getting disposed of! i loaded 55gr sp at minimum last summer. that's all i need as a new reloader is to have something like this happen. i also think its total BS that each book has a different load.
 
There's got to be something else at play here. Ninehorse asked a couple good questions, esp the length issue. Or is it possible the can was mis-labeled? 24 gr with a 69 gr bullet, that should be a long ways from blowing anything up.

I find h335 to be an outstandingly accurate powder in most everything I've tried it in. Work up loads in the summer, or just use caution on winter loads when trying them in the summer. Personally it's never been an issue for me.
 
Please respond on the loaded cartridges overall length (COAL) as the 69 gr. bullet - relatively long - may have been jammed into the rflings if not seated to overall specs and thus raised pressure.

And, if seated in even at an acceptable book length was perhaps compressing your near-max load powder column also raising pressure past the maximum level (thus the blown primer).

Not knowing your actual chamber throating and chamber length this is all speculation.Does your rifle have a 5.56 chamber? A Wylde chamber? Neck dimensions are slightly different than a standard commercial .223 chamber...

Were you using military 556 cases rather than .223 Remington..? brass is typically a little thicker on the 556.

All could have contributed to putting you "over the top" on your particular rifle's pressure safety margin.
 
U have another issue somewhere. Many folks have used H335 for many years and 22gr is a mild load and should not go 3100 so there is another problem beyond powder(or wrong powder). You said you worked up loads ..from what point and why no issues while working up??? Surely you did not start lower than 22gr so at some point something changed
 
Originally Posted By: ohihunter2014looks like my h335 will be getting disposed of! i loaded 55gr sp at minimum last summer. that's all i need as a new reloader is to have something like this happen. i also think its total BS that each book has a different load.

You still haven't figured out that the book is simply a guide. Nothing more...every rifle will have its own max for each load. You really need to do some more reading and research into basic reloading principals. The information you typed here has me quite concerned as to your current reloading practices. Work up loads, pay attention to pressure signs, learn how to read them. Group types, velocity, type of fouling are all key signs of how the load is behaving.
 
So I understand here, you blew it up trying to shoot 24gr of H335 with 69SMK??? If yes, did it happen on the first round loaded with 24gr. or did you shoot a few before it blowed up?

Couple questions, do you know what max COAL is, before touching, with a 69SMK? If you don't know, do you know what bullet weight/s the barrel was throated for?

What was your cartridge overall length after you seated those 69 SMK's?

Are you maybe using a fairly heavy crimp?

Were these rounds all loaded out of a new can of H335 that you have never loaded from?
 
Thank you all so much. Some great questions. New powder. Have used it for 15 years in AR's. Don't crimp. Not compressed load. Barrel is on its last legs. Still shoots 1/2 inch with 55 berger and 25 gr h335. I measured about 0.035 of throat erosion so I thought I'd try some longer bullets thus the 69 ers. I seated them very long but not in the lands. I cycled 10 by hand out of a mag with no issues to check for land clearance. When I shoot I shoot single shot and drop the bolt from half way and check bolt position to assure in battery condition. I do this because I have found setbacks when a jam happens. My neck tension is from .247 empty to .250 loaded with Lapua match brass shot 2 or 3 times max. So in single shot my loads don't bounce off the feed ramps. CCI br primers. Sorry but some questions just came to mind. I don't see a setback. But how else do you explain a ripped up Sierra at 3100 fps? Thanks again for all your great questions. I hope I answered all of them.
 
Just questioning if it is possible that the longer bullet may be setting back in the case as going up the feed ramp because of no crimp.Same result as seating too deep and causing unexplained pressure spikes
 
Originally Posted By: bakerboy Blew up my AR with 24 gr of H335 and a 69 gr Sierra. Their data said 23.8 max. Ok my fault. I thought I had worked up to this load but maybe the much larger bearing surface of this bullet fooled me. Still a basically max book load blows up a gun???? Please note: I only have H335 so it wasn't a powder mixup. I pulled all the remaining bullets and reweighed the powder. 23.8 so no weighing problem. I always check my balance beam with a bullet, so that is not the problem. So I reload the Sierras 69 gr ( .2235 per my mic.) So it's not the wrong bullet. Using 22 gr of H335.(scale again verified with bullet). Now get this, 22 gr is below the minimum of 23 gr which is listed as 2700 fps. My 22 gr loads popped the primers. I didn't know on the first but the second didn't eject and when I pulled it the primer fell out so I immediately stopped. I checked the chrony. 3100 fps. This is not possible. The first bullet was a bullseye and the second never even hit the target. I found a flattened jacket stuck in the plywood below the target. My Krieger barrel looks ok to me. This is some crazy stuff happening. I only know to pull about 50 rounds and start over with different powder unless my barrel is causing this which I don't understand at all. HELP!!!!

Check your case length first. If cases are too long for your chamber, they cannot release the bullet and pressures really skyrocket!

If bullet is jammed into rifling, pressures can also skyrocket. As has been asked, what chamber do you have in your rifle? Standard .223 chambers do not have the leade that 5.56 chambers do and can run pressures up, especially on hotter loads or long loads. Allowing bullet to jump before contacting rifling will lower pressure.



Not a lot of difference in case weight on 5.56 mm brass & .223 Rem. Here is comparison of 3 cases ea.
LC 02 Nato 92.1 gr, 91.6 and 91.1
WCC 14 Nato 93.8, 93.8,94.1
LC11 92.5,92.8,92.9
Win. Commercial 96.093.0,93.8

Both GI 30-06 & 7.62 NATO brass was thicker than commercial, as a rule, however.

One thing you could do is to chamber a loaded round by letting bolt fly, remove round and see if you're getting rifling marks on the bullet. Since you were still blowing primers w/lower load,
OOps, I'm slow typist, I see you have already checked this issue.

I'd take a long hard look at case length, though.

Regards,
hm
 
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Originally Posted By: mbaysinger89Pahntr can you elaborate? "type of fouling are all key signs of how the load is behaving"

Take the rest of the advice and do some more reading in published books. I can type all sorts of information, but it isn't what you need. You need to be well educated in these things before touching a press.

Powder fowling and location can be an indicator. *hint
 
Take this for what you will. I use Lapua brass almost exclusively and I can tell you from first hand experience Lapua brass is without a doubt the toughest brass on the market when it comes to holding primers. So if you were losing primers in Lapua brass at 22grains, that should have been a HUGE sign, for whatever reason, your loads were WAY HOT!!!

With Lapua brass if you even start getting the primers going in easier than normal after only a couple firings you are running things way over pressure.

Also, powders vary from lot # to lot #. I remember a few years back H1000 was giving guys fits because it seemed to be running a lot hotter than it had been. You always want to reduce your load a little when you open a new can, especially, if it's from a different Lot # which is why it's better to buy powder in 5 or 8 lb'ers if it's something you shoot much of.
 
Originally Posted By: pahntr760Originally Posted By: mbaysinger89Pahntr can you elaborate? "type of fouling are all key signs of how the load is behaving"

Take the rest of the advice and do some more reading in published books. I can type all sorts of information, but it isn't what you need. You need to be well educated in these things before touching a press.

Powder fowling and location can be an indicator. *hint

You're going to have to reference a book. After referring to my reloading manuals, hornady, nosler, Lyman, I saw no mention of powder fouling at a certain place being a sign of high pressure. Obviously a carbon ring in front of the chamber will cause pressures to rise, but nothing mentioned in my material about this. I'm not questioning you, just want more information on this.
 


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