Savage 6.5x 284 trophy xp pressure problems

Purchased what was advertised as a new rifle thru Gunbroker. Noticed that the bolt seemed a little loose and sloppy when I worked it. Started noticing increasing pressure signs while breaking in (flattened and cratered primers - ejector marks on case head) I dropped back on loads I worked up that were well within Sierra guidelines. Made several rounds beginning with their starting load 43.7 g of h4831sc behind a 140g Sierra Game King with a c.o.a.l of 2.79 in Norma brass with CCI 200 primer. Shot only one round and the bolt stuck and had to be tapped out. When I finally for the bolt released the brass was stuck to the bolt head and the primer fell out of the case when I pulled the case away from the bolt head. One of my shooting partners thinks it's a head spacing problem. What do you guys think?

What does the fired case look like when compared to an un fired case ? Can you do a basic dimension check with calipers ?

Sent spent case with rifle back to savage today so I can't compare the two. Thanks for the response and if you are so inclined, tell me where we headed with the measurement had it been possible?

I saw this same issue on a friends 6.5x284. We readjusted the factory headspace about .002" and he's still working up loads for it now. We were able to close the bolt on a no-go gauge as it came from the factory. The 6.5x284 I built for my son using a factory 116 barrel did not have any early pressure issues, although the 140 VLD's are seated out too far to provide good bearing surface length inside the case neck just to touch the lands. We may have to do a setback on it just so we can chase the lands as the barrel wears. It only has 40 rounds through it now. Both of the 6.5x284 Savage rifles I've worked on have had this long throat problem.

It would be interesting to see what a new bullet does on one of your spent cases. Yours may have had a tight neck that was causing early pressure problems.

Or you may have created a head space problem by setting up your resizing die wrong. The instructions say to screw the die to the shellplate with a little more to cam over the press. This can be right or wrong depending on a few things. You should have tried a couple factory rounds to compare what was going on. It sounds to me that the case shoulder got pushed back to far and when you got it to fire it kicked the primer and that can ruin a bolt face from the hot jet of gas which acts like a cutting torch on the bolt face.

Would have to agree with Jon on this... Couple questions , How accurate are your scales and secondly do you have a means to measure unfired cases along with fired cases.

The load you mentioned by most accounts should be very mild even if the throat was so short that you were jamming bullets.

Quite frankly it doesn't sound like you can even safely fireform brass so as to properly measure the brass after firing and then properly set up the die.

I would get my hands on a no go gauge and see if it will pass that test , if it does then perhaps your sized brass is terribly oversized with regards to bumping the shoulder back too far.

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Originally Posted by jonbearman

Or you may have created a head space problem by setting up your resizing die wrong. The instructions say to screw the die to the shellplate with a little more to cam over the press. This can be right or wrong depending on a few things. You should have tried a couple factory rounds to compare what was going on. It sounds to me that the case shoulder got pushed back to far and when you got it to fire it kicked the primer and that can ruin a bolt face from the hot jet of gas which acts like a cutting torch on the bolt face.

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Exactly what we saw with my friends rifle. The loaded cartridges were loose enough that they were slamming the bolt face upon firing, creating false ejector marks and unseating the primers making them appear as though they were flattened due to high pressure. Adjusting the headspace an additional .002 to bring it in spec to my go-no go gauges solved that problem. I'm also guessing my friends brass was sized a little too much, pushing the shoulder back enough to compound the headspace issue. I have issues tying this problem to a stuck bolt though since brass springback should allow the bolt to open fairly easy if the headspace was too long and the pressure indications weren't real. I'm guessing that Savage will find one of two things with his rifle, 1) the chamber neck is too tight causing an early pressure spike, or 2) a bad spot in the barrel causing excessive bullet drag that causes a pressure spike later in the course of firing the round. Unfortunately Savage doesn't disclose the problems they find, so we probably won't know what the cause was. Either way, I hope the OP gets his rifle back ready to shoot without any more issues.

try necksizing one and see if it changes, should have 0 headspace if necksized

Check your velocity. You may need to back off the load a little instead of changing headspace.