Blown primer

[Ifishsum]

I've been reloading for 4 years but had a first the other day - a blown primer in a .22-250 Now I'm second guessing myself about this load - it was worked up below book max, and we've fired about 70 rounds out of this batch with no problem whatsoever. It was a hot day, but the other rounds fired on that day were fine, no primers starting to back out or other indications of excessive pressure. This one round obviously expanded the case head pretty good and the primer was stuck to the bolt. The extractor is in la-la land somewhere and the push feed ejector is stuck flush to the bolt face, but otherwise the rifle seems fine, in fact nothing seemed amiss until we opened the bolt.

So while I wait for the new bolt parts to arrive, I'm left wondering if I just somehow overcharged one (I weighed every charge by hand) or if I have a dangerous load for hot weather. Powder is H380 behind a 55gr V-Max. Thoughts?

 

[taliv]

measure the diameter of the other loads you fired that day and see how much they changed?

 

[30Cal]

I think the load you have is not good for hot weather. That's always a concern with ball powders--twenty degrees makes a big difference.

 

[The Bushmaster]

Especially if they are sitting in the direct sun light...

 

[Ifishsum]

The box was in the hot truck for a half hour before shooting too. It's a sweet load and I don't really want to give up on it, but I may need to work on a hot weather load now. When I developed it, the weather was about 60 degrees but I backed off almost a full grain just to compensate for temperature changes.

I haven't measured the case heads yet, but none of the other primers were even loose and there is a dramatic difference in this one case so I'm trying to convince myself that I just made a mistake with one - after all, 7 shots had been fired out of the same box before the mishap. But I also want to be safe.

 

[Ol` Joe]

You don`t give your exact load but Hornady shows 40.6 gr H380 with a 55 gr bullet useing Hornady cases and Win primers as max in their #7 manual.
I`d drop a couple grains no matter.

The fact you blew one primer gives you a hint (as you have shown) that the load is too hot. you`ve gotten away with it so far but I don`t believe in pressing ones luck. Damage to a firearm from excessive pressure is acumulative. The rifle is being stressed by every high pressure shot to some degree and may fail in the future if it keeps up.
JMO.....

 

[Ifishsum]

The load is 39gr H380, Remington case and CCI magnum primer behind a 55gr V-Max. Rifle is a Savage package gun.

 

[Mal H]

I'm going to go against the grain on this. (So what else is new some ask. )

I cut my teeth on 22-250 reloading and have been doing it for going on 40+ years. One of favorite powders is H380, just as it was Bruce Hodgdon's. H380 is not overly sensitive to heat, certainly not the type of heat caused by weather or the inside of cars.

Sounds like you had a pressure excursion that was out of sight. I would find it very hard to blame that on heat. If you didn't burn your fingers chambering the round, it wasn't too hot. How do you explain all the other rounds that seemed to fire normally. Were they cool and the one that busted your rifle was the only hot one?

I would have to go with your first gut feeling on it - you might have overcharged the case. However, it's almost impossible to overcharge a 22-250 with H380. The max charge is in fact a compressed load and that won't cause the pressure spike you experienced.

Is there any possibility that a different powder was somehow substituted in that load? (I know, I know - how could that happen? I have no idea.) Do you ever recall dumping powder back in your H380 container that might have been a different type?

 

[Shoney]

I would like to point out:

The load is 39gr H380, Remington case and CCI magnum primer behind a 55gr V-Max. Rifle is a Savage package gun.

All my information indicates the use of LR not LR MAG primers. Hodgdon uses Winchester LR with start 38.0 and max of 41.0 gr H380. It would seem that the mag primer combination could be the culprit.

I have used mag primers in several rifle loads where standard primers were called for. The difference was that I was using much slower powders.

One example is with a 6mmRem, 100 gr Hornady, IMR4831, CCI LR Mag primer, 26" heavy custom barrel, FN action, which I loaded to max listed (and in those days the data was 2 grains over the max listed today) with no pressure signs, but ES was ??don’t recall exact but less than 15 and groups were 0.30" and under @100yrd. I became very nervous and did not increase the load further. I worked the load up in 50 degree weather and it was a hunting load for colder weather.

Most of the other Mag primer loads in other rifles 6.5x55, 270, 280 and 30-96 flattened primers at or near max in most rifles. I have seen loads go over max with the newer VV powders, but my experimentation was long before they came out.

 

[Ifishsum]

It was a new container and my first of H380. I subscribe to the mantra of only keeping one container of powder on the bench at a time to avoid accidental mixing, so that's not likely either. You've got a point about the load density and max charge, but when I was working up this load I was getting very flat primers at 40 grains and didn't go any further than that. All rounds I've loaded so far are from the same container of powder.

All rounds fired were from the same box at the same temp, and this one definitely spiked substantially over the others as indicated by the case head expansion and imprints on the case and bolt head. All cases had been trimmed and chamfered just prior to loading.

Shoney, I see your point about the primer. For what it's worth, I did not change primers anywhere in the process.

 

[Mal H]

Shoney - does your information include the Speer manuals? From manual #7 to #13, they specifically recommend magnum primers for H380 (CCI250).

I've used CCI250's almost exclusively for my H380 loads with no problems for almost 35 years. In the past few years I've switched to WLR with all large rifle applications for uniformity. The WLR can be used for both standard and magnum applications. I would consider other manuals that recommend WLR to have recommended a [semi]magnum primer, those include Hornady and Nosler.


Ifishsum - you're doing the right things with your powder to keep it uncontaminated. I think we'll have to chalk this one up to gremlins. Really mean gremlins for sure, but you may never know the true cause of the "event".

If you have any rounds from that loading session left, I would seriously consider pulling the bullets and reusing the components with the possible exception of the same charge weight of powder.

 

[Ifishsum]

Thanks for all the suggestions. I looked again and the load is 39.5 gr, not 39.

I'm inclined to blame some gremlin too, considering 57 rds from of the same batch have had no issues. You'd think if the whole batch was marginally overpressure, I'd be seeing some backed out primers or other indications on the other cases from the batch, which there's not.

 

[Hazzard]

Any chance you seated one long (into the lands)? This could cause high pressure.