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wisest.fool

Inactive
I blew up my Remington 700(308).

upon firing, case expanded into bolt face and damaged ejector and I was unable to remove the case without damaging the bolt face. Also damaged bolt handle banging it open with a hammer.

I realize this is my fault. I was shooting reloaded rounds I personally made. So I have messed up somehow. I would like to know how I messed up.

Facts:
-this was bullet #28 of 100 in the case.
-168gn eld-x
-42.5gn IMR 4895
-LC 16 brass (once fired by me at least)
-CCI #34 primers
-Primers on previous cases were flattened but not cratering.
-this is the same load I have shot hundreds of times.
-max charge for IMR 4895 for 168gn jacketed boat tail in my reloading manual states 42.5gn not compressed. Yes I am at the max for my reloading manual(lyman 49th edition). but not over.
-this firearm had about 1200 rounds through it. 75% +/- of those rounds were reloads.

Observations:
2 rounds were SLIGHTLY harder to chamber.
the round that had catastrophic case failure was not hard to chamber.
target was at 450M and previous group was around 8" which is pretty good for my admittedly amateur shooting.(after malfunction I did not go check the target. did check my pants... all clear)

Questions:
1. How did this happen?
2. Should I scrap the firearm or will a new bolt be a safe repair? No obvious signs of cracks or deformation in the reciever or bolt minus the damage it took trying to remove the heavily fireformed case.

Pictures:
Fractured case (head)
fractured case (side view)
Bolt face
Previously fired cases
COL

https://drive.google.com/file/d/1FgCNhPVgncudEJtcJWD53PBwa9hZbIc9/view?usp=sharing
https://drive.google.com/file/d/1Fd3wzkyIL5ljDPzuQfPxkf8hvcdac8tb/view?usp=sharing
https://drive.google.com/file/d/1G9IYZx6MgDkN6sibLb7wgzBKnuIL3MPl/view?usp=sharing
https://drive.google.com/file/d/1FuWXmFzdzHVDlaS9Q4mS_2GOKaSY3G0u/view?usp=sharing
https://drive.google.com/file/d/1G9htneCQsAxcMT3Ojd940X6uDgxPk4ax/view?usp=sharing
 
Were the cases prepped in any way? Did you trim them after sizing? What kind of sizing did you do, full length or neck?

Check the other loaded rounds for high primers, doubt that you had an OOB. I would also pull a couple of the other loaded ones and recheck the load to make sure it wasn't over loaded.
 
-this was bullet #28 of 100 in the case.
-168gn eld-x
-42.5gn IMR 4895
-LC 16 brass (once fired by me at least)
-CCI #34 primers
-Primers on previous cases were flattened but not cratering.
-this is the same load I have shot hundreds of times.
-max charge for IMR 4895 for 168gn jacketed boat tail in my reloading manual states 42.5gn not compressed. Yes I am at the max for my reloading manual(lyman 49th edition). but not over.
Click to expand...

42.5grains in LC brass makes a whole lot more pressure than the same in commercial brass......as you found out. Thicker brass...less volume.

Most manuals make the distinction by saying if using military LC brass cut your loads by 1 or 2 grains......and that's even using starting loads.....one to two grains lower at starting loads and work up. You didn't mention whether the 100 times you shot that load was all with LC brass....was it? If so then maybe you got even more powder in that particular case, somehow.

I've never loaded more than 41.3 grains in my LC brass....but with those loads, primers were spread a little too flat for my comfort....indicating pressure is plentiful, so I backed down to 41 grains on my AR10 clone.

Sorry for your loss, broken rifles are hard to bear, but be thankful you weren't transported to the hospital on a stretcher.
 
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Lots of things sending up red flags here. You had flattened primers prior to this and didn't back off? Hard to close the bolt.....bullets sitting on lands? That can increase pressure quite a bit. Your LC brass holds less powder than Rem brass (less case capacity) and that will increase pressure. Since you were already using max loads, that's a problem. Did you start using a new can of powder....different lot number. A new bolt is NOT a safe repair. Most of the time I hear of these cases it's centered around someone thinking they are close to max and in reality have pushed themselves over in some way. I suspect that's the case here. Send your firearm to Remington and let them check it out and see if it's safe to repair. Start low, work your way up and back off when you see signs of pressure.
 
@TXAZ small powder burn on my cheek where gas came back through the bolt. might have gotten my eye if I hadn't been wearing eyepro. Yes super lucky.

@50 shooter I weighed all the loaded cases... all 262 of them. its all lc 16 brass, but the brass loaded varied from 388 to 392 is 4 gn of variance due to brass? i dunno but as of right now my bullet puller is broken so we will have to wait on amazon. I was unsatisfied with a load i unfortunately made 200 of and it wasn't up to the task. which bullet puller do you use?

@nosecondbest
flattened primers. - did you look at the picture I linked? your opinion on how flattened they look would be appreciated.
lc brass and start low - this load was started at 38gn 4895 and i made 5 bullets then added .5gn and kept going until 42.5 looking for signs of over pressure. I kept the grouping which had the best accuracy. which happened to be the 42.5. At no time was a variable other than the powder changed. so yes lc 16 brass for all 500.
New can of powder - yes i dont have local stores that sell more than 1 lb of powder. so it could very easily have been a new 1lb bottle. no way to tell as i have thrown away bottle.
hard to close bolt - how would i know that the bullet is sitting on the lands and grooves? I chambered a round and then took it out of the gun during load development and could not see marks from the lands and grooves on the bullet. It was also not hard to chamber. I did include a picture of the OAL hoping someone had some experience using military lc brass with eld-x bullets in a remington 700.
 
I don't use anything special, just a kinetic puller to take ammo apart.

Did you trim the brass after sizing it? Did you full length size or did you just neck size the brass?
 
Wow, even if the other ones were a little over max, that one was WAY over max. I don't know if the gun is usable but judging by how much the case has grown I would worry that even the barrel and receiver would be stretched. If you drop a round in the chamber does it rattle around?
 
One possibility you are over looking is could there have been a round with no powder in it. If it was the primer pushed the round just far enough into the barrel to let you chamber another round and shoot.

My guess is a squib caused it. I don't see how an overpressure round, I believe it was either max or little over, would be fine for several rounds and then same load blow a gun up.
 
@gws I was using cci #34 primers which i understand are thicker so maybe what i was used to seeing in primers was not the same with these. i am tracking military brass has a smaller case capacity. waiting on new bullet puller and we will see if the rest of the bullets are actually 42.5gn of 4895. this load was only using lc 16 military brass from load development to failure.

@ 50 shooter my lyman inertia puller broke after many many rounds being pulled. gonna try the rcbs collet puller.

also all were full length resized with dillon dies on a dillon rl550b. i have since moved all rifle loading to a single stage press. not due to this incident just because the progressive press is better for pistol in my opinion.

@ griz my thoughts exactly. the others may have been pushing it but this was significantly more pressure. unlike pistol rounds with fast burning powder, no possible way to double charge this, the powder would fall out all over the place. Also, no the bullet does not rattle around. the case fits securely and i forgot the extractor was broken so i had to tap the buttstock to get the round out.

@ carjunkie yes a squib followed by a live load would do this i am sure. the previous round had normal recoil and was not a squib load. I have in pistols loaded a squib round. i am familiar with the sound and change in recoil. also the barrel is clear. whatever happened the bullet exited the barrel.
 
@50 shooter also, all cases were trimmed using lee trimmer. the one you can chuck in a drill. all cases had military primer crimp removed vie trimming it out versus swaging. i now have a swager and prefer that.
 
In regards to OAL: depending on the ogive of the bullet it doesn't really mean much. You can be on the lands with one bullet at the same time be off the lands with another. Your primers are harder than most others, but the cratering I see is where the firing pin hit. Sometimes the primer will flow outwards and almost appear seamless where it meets the brass. As you stated, you saw indications of pressure in the primer and still used the load. Any time you see any, I repeat ANY signs of pressure you need to back off ASAP. I'm glad you're not hurt. I suggest you change brass and reduce your loads a bit. Good luck in the future and be safe.
 
I checked Hornady's manual, and your charge is below their max. Your COL is their recommended COL. Quickload indicates you would have difficulty loading enough IMR-4895 to cause catastrophic over pressure. Could happen, but it would certainly be a compressed load. Two guesses: barrel obstruction or wrong powder. Since you were shooting prior, I guess wrong powder (or bad powder).
 
That is a huge overload, I doubt 80,000 psi would do it.

4895 is one of the old medium powders, never accused of "detonation" or other unpredictable behavior.
I don't know what it would take to stick a bullet in a rifle, but that is looking good now.
Of course 42 grains of say 4227 would do the job and not look much different from 4895 but making the change would take some real careless manipulation of powder can and measure.
 
The most important thing I learned from reading old reloading manuals from the late ‘40s and early ‘50s is that a person simply can’t estimate pressures by looking at the primers.

Given your COL, how much clearance do you have until the bullet engages?

I load a bullet very long in to a case and push it in- use the specific rifle to seat the bullet, then carefully extract the dummy test bullet and measure the resulting col to compare with my loaded length.

Another thing I learned from old manuals is that even doing everything “right”, always be prepared for things to go wrong in ways you don’t understand. I got old and through many years of doing this sport, I’m at the point where my handloads are deep below factory maximums. But it took me a lot of experimenting and a lot of it we agree not to talk about on this board. It was fun, I learned a lot, and did not blow any guns up only by god’s Grace and good luck.

Glad you are safe, brother! Sorry about your rifle.
 
@gws I was using cci #34 primers which i understand are thicker so maybe what i was used to seeing in primers was not the same with these. i am tracking military brass has a smaller case capacity. waiting on new bullet puller and we will see if the rest of the bullets are actually 42.5gn of 4895. this load was only using lc 16 military brass from load development to failure.
Click to expand...
I figured as much, but that's the first question to ask.

I have heard of people getting variances in LC 7.62 weight, from case to case so that doesn't surprise me. I've never used #34 CCI's. But I did have CCI primer slamfire from a high primer once .... that gets your attention too, but not in the same class as powder burn on the face. My flat primers looked the same as yours, but was with thinner CCI's....but the load was less grains too.

If no squib, you're sure what powder was used, and no double or extra charge, then I'm thinking too long OAL. Least on that case....or a weak case.
I have to admit, your experience is making me rethink reloading and shooting Machine Gun LC brass at least.

My rifle being s. auto, and magazine fed, required seating to fit the mag. Could you have been into the lands on that one?
 
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as per Nosecondbest,
Your LC brass holds less powder than Rem brass (less case capacity) and that will increase pressure.
Click to expand...

Having no means of measuring/comparing case capacity myself, I ask the following with no intention of disparaging this poster.

I have read in many places that LC brass IS thicker than most. On the otherhand I vaguely recall some publication or posts challenging that assumption. Something along the lines of; "LC is using a stronger/harder brass alloy in recent years and is not nearly as thick as was previously used. Therefore the automatic assumption concerning case capacities may be suspect."

If any of that is true, 2016 LC brass is of recent manufacture and may very well have case capacities more similar to commercial brass.

Again, not trying to challenge anyone, just kinda wondering out loud if the new thinner LC brass is fact or fiction.
 
Sorry this happen BUT there is a reason some place .
308 is one i love to shoot and do shoot a lot . I need to ask why the max load ?
I hold my reloads to 2600 fps a 8 inch group what yard 100 - 200 or 500 .
I also have a Remington PPS very good shooter it shoots between 1inch or less at 100 yards useing 168gr bullet at 2600 fps . This Rem was took a lot of deer with this load .
 
At a minimum, there was an issue with the powder charge - either wrong powder, or WAY too much of it.

Based on what I've seen in the past, I suspect you exceeded 100,000 psi (probably more like 105k-110k).

That bolt is toast. The action is probably stretched. The locking lugs in the receiver are probably deformed, and possibly cracked.
Junk it as a hard lesson in why one must be ever-vigilant when reloading.
 
42 grains of IMR4895 in 7.62 NATO M118 match ammo with 173 grain bullets was the norm with
about 50K cup or 60K psi.

I suspect the cause may known until all the reloading details are known.

In 1983, the NRA's 1966 highpower national champion accidentally loaded pistol powder in 308 cases and the first and only shot blew apart the Winchester 70 rifle used to win. He had facial and teeth injuries but survived.
 
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