257 stw blowing primers

[Cheyenne 1]

The rifle is a 700 remington, pacnor 26 inch barrel, trued, oversized threads sleeved bolt, and a few other things.
I got the rifle last winter and worked up a load 81 gr R-25 with a 100gr nosler e-tip. it is loaded .090 off the lands and around 3850 fps. All was good. It put 15 shots into a 1 inch square at 100 yards.

So this fall I took it back out and loaded a few bullets to sight in the scope ( I had swapped out the VX-7 for a Vx-3 LR). That is where it all starts. Now it won't shoot a group. And it wants to blow the odd primer out. So I double checked everything thought the brass was getting used up. Sized up some new Remington brass (7mmstw necked down the same way as the last stuff) same thing. Then I realized I had been using federal 215 primers, last year I had been using CCI magnum primers.

Went back and sized up 3 more brass loaded them with CCI primers and only 80 grs of powder, first 2 shots almost touching (at 200 yards) bolt lift was all good, no extracor marks thinking this is all good now, then the third shot blew the primer out and was hardly on the paper.
Temperature is very similar to last year, same powder.

Any Ideas?? Would like to try something but not sure what.

Thanks

 

[Lefty7mmstw]

The rifle is a 700 remington, pacnor 26 inch barrel, trued, oversized threads sleeved bolt, and a few other things.
I got the rifle last winter and worked up a load 81 gr R-25 with a 100gr nosler e-tip. it is loaded .090 off the lands and around 3850 fps. All was good. It put 15 shots into a 1 inch square at 100 yards.

So this fall I took it back out and loaded a few bullets to sight in the scope ( I had swapped out the VX-7 for a Vx-3 LR). That is where it all starts. Now it won't shoot a group. And it wants to blow the odd primer out. So I double checked everything thought the brass was getting used up. Sized up some new Remington brass (7mmstw necked down the same way as the last stuff) same thing. Then I realized I had been using federal 215 primers, last year I had been using CCI magnum primers.

Went back and sized up 3 more brass loaded them with CCI primers and only 80 grs of powder, first 2 shots almost touching (at 200 yards) bolt lift was all good, no extracor marks thinking this is all good now, then the third shot blew the primer out and was hardly on the paper.
Temperature is very similar to last year, same powder.

Any Ideas?? Would like to try something but not sure what.

Thanks

blown primers= **** hot loads

things to check
1. fouled barrel?
2. same lot of brass, powder, etc. ??-- if not you need to work up your load from no warmer than mid load back to full throttle
3. are you sure you weighed the powder correctly, seated the bullet to the same oal. etc. ??
4. e-tip bullets build pressure like there's no tomorrow-- you have to stay back a bit to account for this like you did with original barnes X

 

[Cheyenne 1]

same lot of powder and primers

barrel was nice and clean
double checked length and powder weight

It just seemed strange I shot about 50 or 60 this spring after I had it all dialed in and all was good, accurate, no signs of pressure, bolt lift was good, no flattened primers, no extractor marks.
It is all good then all of a sudden it will blow a primer out.
I just remember reading somewere about the 257 seeming to have an issue with this.
I have another one of these in 257 stwAI that I shoot a 110 accubond . And I have one in 7mm stw.

 

[SidecarFlip]

I'm curious, are you hand seating primers or seating on the press and how do they seat? Is there a definite resistance or not?

Just because the brass is new don't mean the primer pockets are good.

Sounds hot to me too but you could have a pocket issue....

 

[mt_archer]

Extreme rounds like this are squirrelly for sure. I quit rl25 and went to ram shot magnum when it was first around for 257 stw. Even at that, i never reloaded my brass, half wouldnt hold primers. More recently I went to retumbo. Not quite the velocity but more stable. Etip is pretty bad, too. That combo is likely verge of hand grenade, even just a few thousandths closer to rifling or few degrees warmer could do it. If everything was identical, I would suspect a carbon ring around six inches ahead of chamber. If you push a nylon brush slowly, feel for resistance. If there is a rough spot, it could be carbon ring. Might get it with foam, otherwise, use slow back and forth with jb bore paste and kroil, or something similar. Just don't use metal brush. If no carbon ring, I'd be grasping at straws.

 

[Cheyenne 1]

I seat all my primers by hand. They all seemed to feel normal when seating them.
I had tried ramshot and retumbo, it didn't work all that well for me.
I hadn't heard of the e-tips causing pressure problems, I guess thats why we have these forums to ask questions. I have some swifts I could try.
I will also check with a brush to see if there is a carbon ring.
Hopefully this week the wind will go down and I will try and see if I can get this figured out.
Thanks

 

[orch]

I had a 25-06 (factory savage) that started doing this after about 400 rounds down the pipe.... Didn't matter what I did load wise ie. down loaded to mild loads, different bullet and powder combos.... It would shoot a couple shots accurately then I'd get a blown primer and either wicked bad fliers or vaporized bullets in flight... Turns out it had some nasty fire cracking... Gunsmith that bore scoped it said it was the worst he'd ever seen... Turns out long firing strings on hot days in the gopher patch are a bad idea
I say take it to a smith and have him take a look down the barrel...

Orch

 

[lloydsmale]

had a 264 mag ruger that the same happened too. About 200 rounds of hot ammo down the pipe and it started blowing primers with even mild loads. Bore scope showed extream scaling in the first part of the barrel. Sent it to ruger and they were nice enough to replace the barrel for free even though i was my fault. Backed the loads off a bit in the new barrel and its fine after over 500 rounds.

I had a 25-06 (factory savage) that started doing this after about 400 rounds down the pipe.... Didn't matter what I did load wise ie. down loaded to mild loads, different bullet and powder combos.... It would shoot a couple shots accurately then I'd get a blown primer and either wicked bad fliers or vaporized bullets in flight... Turns out it had some nasty fire cracking... Gunsmith that bore scoped it said it was the worst he'd ever seen... Turns out long firing strings on hot days in the gopher patch are a bad idea
I say take it to a smith and have him take a look down the barrel...

Orch

 

[Lefty7mmstw]

had a 264 mag ruger that the same happened too. About 200 rounds of hot ammo down the pipe and it started blowing primers with even mild loads. Bore scope showed extream scaling in the first part of the barrel. Sent it to ruger and they were nice enough to replace the barrel for free even though i was my fault. Backed the loads off a bit in the new barrel and its fine after over 500 rounds.

You learn something new every day. Each barrel I've go bad has simply lost enough rifling that the accuracy started to fall off, but I move 'em early(while they shoot fine yet) so that may be a later developement. I've never had firecracking bad enough to cause the trouble you speak of, but I don't doubt it. Even my 7rum had simple throat wear and no real firecracking.

 

[lloydsmale]

that was the prognosis that ruger gave me when they replaced it too.

 

[SidecarFlip]

This isn't 200 down the tube or even 100 or even 50. It's 15. I could see firecracking/excessive heat if the 15 were in rapid succession, I don't believe they were????

Something's fishy.....

 

[Cheyenne 1]

Well. I just bougjht a new bore scope for the guys at the shop to inspect cylinders and such. Gueess I will bring it home tonight and have a look and see how bad it looks. One other thing I have never rapid fired it. I know these are hard on barrels. I just expected it to last a little longer.

 

[orch]

This isn't 200 down the tube or even 100 or even 50. It's 15. I could see firecracking/excessive heat if the 15 were in rapid succession, I don't believe they were????

Something's fishy.....

He said he put 15 shots in a one inch square.... I assume that is with his load he worked up after load developement... So I'd think he had more than 15 shots through it... Not trying to start an argument, just saying....

Regardless there were only two days I pushed the 25-06 on hot days that probably caused the fire cracking and they consisted of about 20 shot rapid fire sessions where I didn't let the barrel cool down between shots and smoked the barrel.... Atleast that's what the gunsmith told me did it.... So it doesn't take much according to him.... So yah as you said rapid succession....

I guess the OP would be the one to ask.... What was the total round count on the barrel?

Orch

 

[SidecarFlip]

He said he put 15 shots in a one inch square.... I assume that is with his load he worked up after load developement... So I'd think he had more than 15 shots through it... Not trying to start an argument, just saying....

Regardless there were only two days I pushed the 25-06 on hot days that probably caused the fire cracking and they consisted of about 20 shot rapid fire sessions where I didn't let the barrel cool down between shots and smoked the barrel.... Atleast that's what the gunsmith told me did it.... So it doesn't take much according to him.... So yah as you said rapid succession....

I guess the OP would be the one to ask.... What was the total round count on the barrel?

Orch

You may be right, I may have read it wrong. I didn't account for load work up, just the 15 shots......

........."The rifle is a 700 remington, pacnor 26 inch barrel, trued, oversized threads sleeved bolt, and a few other things.
I got the rifle last winter and worked up a load 81 gr R-25 with a 100gr nosler e-tip. it is loaded .090 off the lands and around 3850 fps. All was good. It put 15 shots into a 1 inch square at 100 yards.

A bit more than 15 but how many more?? Sixty four dollar question and it may, in fact be uchered.

Sort of like my hunting rifles. I never expect to shoot out a barrel because they get a load worked up and they sit until needed. Now my 223's get the bejesus shot out of them.