i just started having pierced primers after 1200 rounds on a 6gt build. Im using cci 450 magnums , hornady brass and 34.2gr varget. Ive damaged 2 TT diamonds during this issue, Ive had 5 thousandth taking off the firing pin thinking I had a protrusion issue and still piercing primers. Any help would greatly be appreciated.
Gunsmithing Piercing primers in Remington700 6Gt
- Thread starter ckelley86
- Start date
Im using a rcbs 1500 and my speeds are 2920fps and yes you are correct they where designed for 700 clones but they work only thing is you have to operate the bolt stop with a small pick
Im thinkinh the firing pin needs bushed or a new mainspring.
Could also be the firing pin hole that is a little too big for the firing pin.
You’ll have to find a smith that will bushed the bolt face and turn down the firing pin. I think Gregtan used to do it. What’s the diameter of your firing pin now? My guess would be like .085ish. I had similar issues with an AR10 in 6.5 creed I used a JP HP small firing pin bolt and the problem disappeared.
There is absolutely no reason to shorten the firing pin. It will only cause future problems. Get another gunsmith. You're blanking ( the more appropriate term) primers because of pressure. You nor anyone else pierce primers. Pressure is measured in pounds per square inch. The primer cup is rated in pounds per square inch based primarily on cup thickness. The firing pin can and does support, to some degree, the primer cup. Firing pin fit, shape and diameter all influence how good or not so good the pin supports the primer cup reducing flow back into the firing pin hole. That flow when it reaches critical mass blanks the primer. A disc is blown back into the bolt with a great amount of force. So much so that the firing pin goes all the way to the rear of it's travel. Some after market triggers are well known for breaking after blanking a primer. If you reduce the diameter of the firing pin hole you reduce the pressure on the primer cup. It's as simple as that.
Reduce your load or have the bolt and firing pin modified.
In your case I have to ask about your cleaning regime. Carbon build up and heat checking can and will increase pressures. Any change in components?
Reduce your load or have the bolt and firing pin modified.
In your case I have to ask about your cleaning regime. Carbon build up and heat checking can and will increase pressures. Any change in components?
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No change in components other than a new lot of 450's and a carbon ring about 300 rds ago which was causing pressure issues but never a pierced primer only ejector marks and haevy bolt lift was the symptoms. But now im piercing primers and its random it shoots great no issues and then out of no where it will pierce.
There could be something with the primers but if there is you were/are the ragged edge anyway. You're going to have to manage the pressure.
700's all can have this issue. Can being the key word there. Too much pressure and everyone of them will have problems. Custom actions come with either a reduced diameter firing pin with matching hole in the bolt or just a much better fit with the larger diameter.
Just reducing the diameter of the firing pin without bushing the bolt is going to make the piercing worse, as the clearance between the pin and the edge of the hole is greater allowing for more flow of the primer under pressure. The recommendation to get another 'smith was a good one. I would send the bolt off to gretan https://www.gretanrifles.com/ like thousands of others have and your problem will be fixed. fast turn around, good work at a reasonable price.
Sounds like a carbon ring. In the throat area. You made a big mistake messing with the firing pin length.
To help you better, describe your cleaning process. I know you stated you cleaned it about 300 prior but did you really clean it.
Your shooting an overbore cartridge which is prone to a carbon ring.
Carbon ring causes overpressure.
Give us that info and we will be able to help better.
Thanks,
Thud
To help you better, describe your cleaning process. I know you stated you cleaned it about 300 prior but did you really clean it.
Your shooting an overbore cartridge which is prone to a carbon ring.
Carbon ring causes overpressure.
Give us that info and we will be able to help better.
Thanks,
Thud
I scrubed out the carbon ring about 300 rounds ago i knew i had a pressure issue because i had hard bolt closure and hard bolt lift and noticeable ejector marks but one thing i didn't have was pierced primers. Once the ring was removed everything ran great and chambered beautifully, I use Butch's bore shine and cloth patches and brass brush. Pierced primers pretty much came out of nowhere at a match and reuined my trigger.
I don't think you got it out.
How do you know if you got it out, check with a borescope
Try this;
Get some Bore tech carbon remover and the copper remover.
Get a proper diameter aluminum jag(removes false positive copper readings.) Use the Pro shot patches they are the best.
wet down the bore with the carbon remover till the patches are clean. Use a clean patch each time. They are cheap.
Follow the directions on the carbon remover.
Then wen you think you got it take an oversized bronze brush example 6mm use a 7mm. and put the carbon remover on the brush and put the brush tight in the neck and throat area and turn the brush a bunch of time either cw or ccw but always in the same direction. Because the carbon will get very hard and it's like a diamond. The a few tight patches in the throat area with the carbon remover to pick up and remainder of the carbon.
Then use the CU remover to get rid of the copper in the barrel.
Do this very time you shoot to prevent the ring from forming. Since it's a overbore cartridge.
JB is good for the barrel Issio is better for the carbon ring but requires more cleaning to get the stufff out.
Also does this happen in hot weather or cold and mild.
During the summer pressure will increase and give you the above symptoms.
Load development in cooler times with a good speed can not work well in warm weather will heat things up and the case pressure will increase.
Let me know if this helps. And get a new firing pin.
Thud
How do you know if you got it out, check with a borescope
Try this;
Get some Bore tech carbon remover and the copper remover.
Get a proper diameter aluminum jag(removes false positive copper readings.) Use the Pro shot patches they are the best.
wet down the bore with the carbon remover till the patches are clean. Use a clean patch each time. They are cheap.
Follow the directions on the carbon remover.
Then wen you think you got it take an oversized bronze brush example 6mm use a 7mm. and put the carbon remover on the brush and put the brush tight in the neck and throat area and turn the brush a bunch of time either cw or ccw but always in the same direction. Because the carbon will get very hard and it's like a diamond. The a few tight patches in the throat area with the carbon remover to pick up and remainder of the carbon.
Then use the CU remover to get rid of the copper in the barrel.
Do this very time you shoot to prevent the ring from forming. Since it's a overbore cartridge.
JB is good for the barrel Issio is better for the carbon ring but requires more cleaning to get the stufff out.
Also does this happen in hot weather or cold and mild.
During the summer pressure will increase and give you the above symptoms.
Load development in cooler times with a good speed can not work well in warm weather will heat things up and the case pressure will increase.
Let me know if this helps. And get a new firing pin.
Thud
I beg to differ. I use Varget in Texas. During the summer on y 6br and 223's and a 308( I have one that likes it) I need to lower y charge to the pressure problem.
Also Varget at times varies from lot to lot. It will speed up.
Also Varget at times varies from lot to lot. It will speed up.
Have u lost accuracy.
also I shoot for accuracy not speed. There usually several nodes that the rifle shoots at well. U set up your rifle in the cold. Have u changed lots of powder. Primers. What has changed from initial setup in your components.
also I shoot for accuracy not speed. There usually several nodes that the rifle shoots at well. U set up your rifle in the cold. Have u changed lots of powder. Primers. What has changed from initial setup in your components.
Accuracy is great i did a ladder test in late march 34.2 was where i found my node 1/4 moa at 500yrds so i just stuck with it Accuracy has never been an issue im using a magneto speed for chronograph i dont chase speed either but i do pay attention to it
If you had a carbon ring 300 rounds ago and have not changed cleaning methods it could very well be the problem again. Give it a good scrubbing with JB and back the powder down and work back up if your issue goes away . Rem 700 will surely benefit by having the bolt bushed and firing pin turned down . Just my opinions of course, good luck .
