Need pressure schooling !

[SavageMark]

Savage 12 action (with corresponding heavy Savage bolt lift) Shilen 6BR Barrel . 107 smk , 30g Varget . My wife was a having a difficult time opening bolt . You could feel fired case causing pressure again the bolt . So me being a genius I increased headspace from .001 to .004 thinking the extra room would help . It didn’t . Even a powder puff load of 28.1 made brass .004 longer and give a small sticky opening . Im enclosing 2 pics . One of fired cases and one of a mark all the way around bullet just from chambering . Any opinions greatly appreciated . Thx

Mark

 

[Dolomite_supafly]

Take a sharpie and mark the bullet, the neck, the case head and the shoulder. Chamber, lower the bolt handle then raise the handle and go back down a few times. Then extract and look at the case. The shiny areas will tell you where the problems are.

Could be the bullet jammed into the lands or the case mouth is too long and it is getting crimped around the bullet by the throat when chambering. Either of those can spike the pressure, especially if you are at or close to max.

Primers look a little cratered.

And resistance or the OAL changing after chambering?

 

[SavageMark]

Take a sharpie and mark the bullet, the neck, the case head and the shoulder. Chamber, lower the bolt handle then raise the handle and go back down a few times. Then extract and look at the case. The shiny areas will tell you where the problems are.

Could be the bullet jammed into the lands or the case mouth is too long and it is getting crimped around the bullet by the throat when chambering. Either of those can spike the pressure, especially if you are at or close to max.

Primers look a little cratered.

And resistance or the OAL changing after chambering?

I will do the sharpie tonight and get back with you . Also I’ll check O.A.L. after chambering and I’m pretty sure there was resistance chambering a fired case also . I’ll give u more accurate info this evening .

Thx for your help !

Mark

 

[SavageMark]

Should light load brass grow as much as a full load ?

 

[BRGUY]

A couple of your primers still have good radius around them, but most don't.

If you were not having pressure signs, I would suggest bushing the firing pin hole, match the firing pin diameter and add a heavy duty firing pin spring.

But!

Since you have heavy bolt lift and you are showing pressure signs, I would suggest backing off your powder charge a couple of grains and approach your guns maximum load with caution, and in 2/10th grain increments, especially if you are shooting in HOT weather.

Either way, I would definitely change loads.

To answer your question - no, it should not.

 

[SavageMark]

A couple of your primers still have good radius around them, but most don't.

If you were not having pressure signs, I would suggest bushing the firing pin hole, match the firing pin diameter and add a heavy duty firing pin spring.

But!

Since you have heavy bolt lift and you are showing pressure signs, I would suggest backing off your powder charge a couple of grains and approach your guns maximum load with caution, and in 2/10th grain increments, especially if you are shooting in HOT weather.

Either way, I would definitely change loads.

To answer your question - no, it should not.

I did shoot a round with 28.1 grains and cratering was better but bolt was still sticky.

 

[SavageMark]

A couple of your primers still have good radius around them, but most don't.

If you were not having pressure signs, I would suggest bushing the firing pin hole, match the firing pin diameter and add a heavy duty firing pin spring.

But!

Since you have heavy bolt lift and you are showing pressure signs, I would suggest backing off your powder charge a couple of grains and approach your guns maximum load with caution, and in 2/10th grain increments, especially if you are shooting in HOT weather.

Either way, I would definitely change loads.

To answer your question - no, it should not.

I did shoot a whole box 50 rounds with the 30 grain load . It was accurate . If I could shoot a whole box (except for a little stick of bolt ) isn’t that under max for the gun ? I’ve never had a popped primer !

 

[Jdne5b]

You're either jamming hard or have a carbon ring based on that bullet pic.

 

[SavageMark]

You're either jamming hard or have a carbon ring based on that bullet pic.

Don’t think I’m jamming , there isn’t any pressure seating cartridge . And forgive my ignorance , can a carbon ring happen in less than 300 rounds ?

 

[BRGUY]

I did shoot a round with 28.1 grains and cratering was better but bolt was still sticky.

It still sounds like you need to back your load down a little bit further.

 

[mike a]

Mark, I have a Shilen stainless select match in 6br on my custom action. I can not get 30 grains of Varget without getting pressure. 107 smk. It's not a jam problem or headspace, carbon ring or or or! Tried two different lots of also. It may be my die not sizing the base enough. Maybe! I've got another barrel coming and am going to go the Harrels die route. Check out there web site about 6 br dies. I'm using 28.2 and get awesome accuracy. Remember Accuracy is king, not velocity. Mike

 

[338 dude]

View attachment 1121694 View attachment 1121695 View attachment 1121694 View attachment 1121695 Savage 12 action (with corresponding heavy Savage bolt lift) Shilen 6BR Barrel . 107 smk , 30g Varget . My wife was a having a difficult time opening bolt . You could feel fired case causing pressure again the bolt . So me being a genius I increased headspace from .001 to .004 thinking the extra room would help . It didn’t . Even a powder puff load of 28.1 made brass .004 longer and give a small sticky opening . Im enclosing 2 pics . One of fired cases and one of a mark all the way around bullet just from chambering . Any opinions greatly appreciated . Thx

Mark

Judging from the mark on the bullet it looks like you were jamming into the lands which will definitely raise pressures even on the smaller powder charge back off the bullet .020 and see if the problem continues the marks on your primer around the firing pin are normal some people have their bolt bushed to be tighter around the firing pin but it is not necessary also check the neck outer diameter on a fired case add .001 that should be extremely close to the neck diameter of your chamber you should have .003 maybe even .004 clearance From a loaded round you may have a tight neck chamber which would not release the bullet properly also causing higher pressures

 

[SavageMark]

Judging from the mark on the bullet it looks like you were jamming into the lands which will definitely raise pressures even on the smaller powder charge back off the bullet .020 and see if the problem continues the marks on your primer around the firing pin are normal some people have their bolt bushed to be tighter around the firing pin but it is not necessary also check the neck outer diameter on a fired case add .001 that should be extremely close to the neck diameter of your chamber you should have .003 maybe even .004 clearance From a loaded round you may have a tight neck chamber which would not release the bullet properly also causing higher pressures

Loaded round neck measures .2695. Fired case neck measures .272 . It’s supposed to be a .272 no turn neck .

 

[SavageMark]

Take a sharpie and mark the bullet, the neck, the case head and the shoulder. Chamber, lower the bolt handle then raise the handle and go back down a few times. Then extract and look at the case. The shiny areas will tell you where the problems are.

Could be the bullet jammed into the lands or the case mouth is too long and it is getting crimped around the bullet by the throat when chambering. Either of those can spike the pressure, especially if you are at or close to max.

Primers look a little cratered.

And resistance or the OAL changing after chambering?

Ok ! Did the sharpie . The only place marker was removed is the same place on the bullet that’s in the pics .

No O.A.L. change . 2.39 . So I might just be in the lands a little . Will seat it .02 deeper and recheck !

 

[SavageMark]

Mark, I have a Shilen stainless select match in 6br on my custom action. I can not get 30 grains of Varget without getting pressure. 107 smk. It's not a jam problem or headspace, carbon ring or or or! Tried two different lots of also. It may be my die not sizing the base enough. Maybe! I've got another barrel coming and am going to go the Harrels die route. Check out there web site about 6 br dies. I'm using 28.2 and get awesome accuracy. Remember Accuracy is king, not velocity. Mike

I forgot to mark the case head like someone told me . I’ll have to do it again . But I just measured a brand new case at the head and it measured .4695 and a fired and sized case measures .472 . So maybe I need a new die also !

 

[338 dude]

Loaded round neck measures .2695. Fired case neck measures .272 . It’s supposed to be a .272 no turn neck .

A little tight .002 minimum .003 or .004 is better

 

[Dusty Stevens]

can a carbon ring happen in less than 300 rounds ?

If you havent cleaned it out you should have about 250rds ago

 

[SavageMark]

If you havent cleaned it out you should have about 250rds ago

I have cleaned barrel 2 or 3 times in those 300 rounds . How can I see if there is a carbon build up ?

 

[Dusty Stevens]

I have cleaned barrel 2 or 3 times in those 300 rounds . How can I see if there is a carbon build up ?

If you dont have a borescope you can feel it. If you havent addressed it just assume you have an awful one and clean accordingly

 

[SavageMark]

If you dont have a borescope you can feel it. If you havent addressed it just assume you have an awful one and clean accordingly

I only use cloth patches around a nylon brush . Is this sufficient ?