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These are pics (3rd from top)of some primers that seem to have failed to contain gases. The primers are rem 9-1/2 purchased in 1981. The cases are once fired .30-06 sized and loaded for .338-06 loaded with Varget powder and 225 gr Hornady SST bullets.



Right case: 49.5 gr Varget chrono @ 2385 fps

Middle case: 51.0 gr Varget @ 2464 fps

Left case: 52.0 gr Varget @ 2539 fps



I loaded 30 rounds with Varget powder in .5 grain inciments from 48.5 gr to 53.0 grs with 3 rounds in each step.



As you can see by the pics there were no other primer failures in the same powder load or other lighter or heavier loads. Each load of powder was weighed on my Hornady/Pacific beam scale before being funneled into the case. All bullets were seated .050" off the lands. Bullets were not crimped in cases. All these things being equal, what could be the cause of these failures?



I edited this after freds response.

Yours? There are a few there that need to back off a grain I think.

Hummmm....



Your loads fall within what I found to be the useful loading range:

Varget From 36.7 grains to 52.0 grains

Winchester WLR Primer



But I also noticed another little problem with your cases. There is a definate mark on the primers where the firing pin hole on the bolt face is located.



Questions I have:



What did you use to seat the primers?

Did you fully seat the primers?

Did you uniform or clean the primer pockets after you tumbled the cases and before you seated the primers?

What are the primer pocket dimensions on the "bad" cases compared to the primer pocket of the "good" cases.

Personally, I would try to look at other powders.

I use IMR 4064, 50 grains of it will give 2500 fps with any bullet weights from 200 to 250. I think that is a neat feature.

While some guys also recommend H 414 or W 760, I use 62.5 grains of H 380 or 60 grains of W 748 with a 225 grain bullet. Velocity exceeds 2750 in a 24 inch barreled model 70 and the accuracy is superb.

I have never been part of the crowd that is overly impressed with Varget, in any cartridge.

Good luck with it.

Cheers and Good shooting
seafire

Ricciardelli,

I used a RCBS hand priming tool and fully seated with hand pressure. I inspect each primer after seating for unform depth. I do this by eye and a finger nail. Crude, but it has not failed me until now(?). I did not uniform the primer holes and did not measure the holes either. The primer holes are cleaned on my RCBS case prep staion thing. It has several spinning devices that can have items screwed into them. The primer pocket was cleaned on that with a small wire brush designed for primer pockets. I also deburr the inside of the primer hole from inside the case. What tool do you use to measure primer pocket size/dimension?

Primer Pocket Uniformer

But there are some others that are cheaper. This one has two cutters, large rifle/pistol or small rifle. You would have to set the depth between the large rifle/pistol.

I think you have a lot going on there and most of it concerns me. The load isn't that extreme. But, the bottom of your cases raises a lot of concern. As was mentioned the ring around the firing pin. The shape of the primer the gas leakage. Are your cases too long? Excess headspace. Too much play around the firing pin. Just looking at the cases there are few I would fire again.

Just my 2 cents. Time for coffee.

In my experience IMR 4320 is about the optimum of the IMR powders for the .338/'06. There may be an Alliant RE series powder that is just as good, but I don't know which one it is. IF there is nothing wrong with your bolt face, I must suspect that the Varget loads are too hot for your rifle, IF your primer pocket stretching is occurring with ligher loads as well as the top one! I would try a different powder.

Okay, you are using the same hardware that I use, the RCBS hand primer, and the RCBS CaseMate machine.



Since the problem is not with all your cases, I would have to go along with the suggestions that you use a different powder.



I would try:

H-414 From 56.0 grains to 61.0 grains

Winchester WLR Primer



(I must admit that I am not too impressed with Varget. I have been trying for 2 years to find a load for one of my .22-250's and one of my 6mm Remingtons using that powder, and the results have been much less than desirable.)

It appears to me that your primers are cratering so the load is too hot for some reason, perhaps you need to trim your cases, cut back a grain or two, change powders, change primers (try Fed. 210s),...

A better powder in the 338-06 or its improved versions is IMR-4320. In fact it is the best powder...

Atkinson may be onto something here! I apologize for not thinking of this sooner, but if the cartridge cases aren't freely releasing the bullets on firing, or if some do and some don't, it would certainly explain why you could get a blown primer with a smaller powder charge in one piece of brass and not in the next one with a heavier charge!



Try this: See if a new bullet will fall freely into the fired cases before you let a die touch them. IF a case is too long, or the neck of a case is too thick to the point where bullets aren't being released correctly upon firing, you could get blown primers, OR WORSE, with a powder charge that is perfectly within reason otherwise. If this is happening, some cases may need trimming, turning, or both so the bullet will easily fall into the fired case.

Ah, yes, Rem 9-1/2 primers from the '80s, I remember having the exact same pinholes in the edge as you show. Lots of folks back then reported this problem with 9-1/2s and I can't remember if Remington actually issued a recall or they just changed their manufacturing quickly and later lots were OK. Dump those primers for something more modern and you'll have no more pinholing.

Odd Ball:

I have very similar problems with my 338-06, it seems I have to keep the powder charge weights lower than most of the other guys. I get flat primers, an occasional blown one as well, and lots of bolt clicking and sticking. It may have something to do with the 338's expansion ratio, at least in my rifle. What really ticks me off, is I owned a 35 Whelen, still do, before I built the 338, and I thought I could get the same velocities, I.E. performance as the Whelen, with a little better B.C, but I can't. 2400 fps with a 250 grain bullet leaves a little to be desired if your Whelen is putting the same bullet down range at 2650. Try a different primer lot, and 4064 or 4320. Good luck

Jerry