Pressure issue (HeadSpace? )

[fguffey]

Thank you for your reply. I was firing test loads in a new 6.5 CM and later I noticed that the cases would not let a bullet slip in. I was shooting near max with both H4350 and IMR4350 and both powders shot best at just under max and at 2950 fps using a 123 Amax. No pressure signs at all.

I make all efforts to eliminate bad habits, when at the range and firing a rifle I am not familiar with I shoot the first round (and then one of those 'and then moments'), I stick the bullet of the next round to be fired into the neck of the fired case. If the bullet does not slip on to the neck of the first case fired I stop shooting. I put the rifle away with the ammo and start shooting something else. There is something wrong, who knows? In the sequence of events the neck of the case expands and releases the bullet, meaning if the neck expands when fired the bullet of the next round should slip into the neck with no resistance and there is a good chance the bullet will only touch the neck on one side.

F. Guffey

 

[fguffey]

A very disciplined reloader called to include me into a deal he was working on. To get started he had 80 7 Remington cases to give me. It was not long before I drove over to get the information and the cases. As soon as saw the cases I informed him we needed to go talk to the reloader/shooter/writer/author/machinist about his fired cases. TOO LATE! He died and the family was selling his shop. I suggested we find the rifle; too late, the family did not know who purchased the rifle. And then the disciplined reloaders ask me what was my concern?

The 7 Remington Mag cases took on the appearance of having a black glass glaze on all of the necks, meaning the case necks were too tight for the chamber and the same glaze/glass looking stuff also reduced the inside diameter of the neck in the chamber.

F. Guffey

 

[7Saum]

There are many that paint with wide brushes, to them everything has head space and all gages are head space gages. For me it is not that complicated, my chamber has head space my head space is measured from the datum/shoulder to the bolt face; and that is it, my cases do not have head space. My cases have a length, I use the length of the case from the shoulder of the case head to off set the length of the chamber. The difference in length between the chamber and case is clearance. I can have a lot of clearance, I can have 'zero' clearance and I can have a crush fit. And then there is relating head space to pressure.

The length of the case from the shoulder to the case head can have an effect on pressure, it should not be a problem for those that can keep up but to do so the reloader must know the clearance. Seating the bullet to or into the lands can have an effect on pressure. When seating into the lands the reloader must understand when seating to or into the lands not start with maximum loads.

And then there are soft case heads that imprint on the bolt face.

I would suggest measuring the diameter of the case head before and again after firing, it is a god ideal to start with new cases. I have fired cases once and then had to take the rifle apart to remove/find the primer. I have fired cases once and expanded the case heads .100". The case heads crushed, the case heads expanded and shortened, the primer pockets opened and the flash holes took on the appearance of having been drilled out. When testing rifles that are suspect I choose to use cases with thick case heads. I have older Remington (R-P) cases with case heads that measure .260" thick from the cup above the web to the case head. When crushing case heads a thick case head is safer than a thin case head. I have thousands of 30/06 military cases like LC with case heads that measure .200". I know, that is confusing but I believe the R-P cases had an additional .060" safety built into them when testing suspect rifles.

F. Guffey

Hi,
Thanx for the info,been gone for awhile,I will see if I can figure this out,appreciate the input..

 

[7Saum]

Set your re-sizing die to bump the shoulder back .002" ................. You'll need a comparator (hornady lnl guage) to do this accurately................ This is a "must have" tool for any serious re-loader concerned about cartridge H/S. ....... In the mean time set up your resizing die and adjust it in VERY small increments like 1/32 of a turn until your bolt closes on the fired case with no resistance. ...... Since you have a variety of brass, some softer than others, do this for each type of brass. this will allow you to put the possible H/S issue to bed and allow you to concentrate on other possibilities.

Hi,
Thanx for the info,I will be purchasing a comparator,I will give it a try..sorry for the late reply been gone for awhile..

 

[fguffey]

Set your re-sizing die to bump the shoulder back .002" ................. You'll need a comparator (hornady lnl guage) to do this accurately................ This is a "must have" tool for any serious re-loader concerned about cartridge H/S. ....... In the mean time set up your resizing die and adjust it in VERY small increments like 1/32 of a turn until your bolt closes on the fired case with no resistance. ...... Since you have a variety of brass, some softer than others, do this for each type of brass. this will allow you to put the possible H/S issue to bed and allow you to concentrate on other possibilities.

The Hornady/Sinclair tool is not a compulsory tool, it is nice but many users have required theropy because they could not get the chamber, case and die to agree. It helps when using the Hornady tool to learn how to verify. When verifying the Hornady tool the reloader must understand they use a ‘be kind to your case philosophy’; Hornady uses a radius at the opening of the tool. Something reloaders are unaware of is ‘the datum’ uses a sharp edge on the datum and the hole for the datum is absolute, meaning the hole for the 30/06 datum is .375” in diameter.

You'll need a comparator (hornady lnl guage) to do this accurately

Not true, a reloader with a Wilson case gage can accomplish the same task if they learn to measure before and again after. The Wilson case gage is a datum based tool. The problem reloaders have when using the datumn base tool is measuring from the datum, I use a straight edge and a feeler gage, some use their thumb nail and others just sight it in. The same goes for sizing after firing, measure before sizing and again after sizing.. because? How else can a reloader determine if the case is shorter from the shoulder to the case head after sizing. I know, everyone bumps the case shoulder back to accomplish the magic .002" clearance. My cases do not have head space and I find it impossible to move the shoulder back, I can shorten a case from the shoulder to the case head, I can not shorten the case by moving the shoulder back.


F. Guffey

 

[ireload2]

Classic

[QUOTE="fguffey, post: 36851124, member: 1279829"
My cases do not have head space and I find it impossible to move the shoulder back, I can shorten a case from the shoulder to the case head, I can not shorten the case by moving the shoulder back.


F. Guffey[/QUOTE]

 

[dkhunt14]

I always read in books if you bump size a case too far it will stretch upon firing, possibly causing case head separation from too much headspace. LOL Matt

 

[ireload2]

According to Guffey you can push the shoulder back to the rim and you will still not have excess head space since by definition the case has NO HEAD SPACE. All head space is in that nasty rifle chamber. Even so your cases can still come apart.

I always read in books if you bump size a case too far it will stretch upon firing, possibly causing case head separation from too much headspace. LOL Matt

 

[rifleman700]

Thanx,here is what I did pics to follow (hopefully )
52.5 gr rl17 -Norma Brass 145LRX OAL 2.96
55 gr -H4350-Rem Brass 145LRX OAL 2.96
Factory Nosler Custom 160 accubond 2.75
COAL I am touching lands at 2. 98 I put black marks on case to show(ejector mark in between ) I use Redding type S bushing style dies..
Thanx..

This does not have anything to do with your case head swipes but let me give you a bit of advise when it comes to your reloads.
1. Barnes LRX bullets need to jump. It appears you have them seated too close to the lands as I read it. Start at .040-.050" jump and then test seating deeper from there. This can be very dangerous if not done right. Solids like the Barnes LRX do not obdurate like cup and core bullets and need to jump to prevent pressure spikes.
2. Clean your bore before testing bullets with different jackets. Nosler jackets are harder and copper deposits left in the bore will tear the softer Barnes bullets.
3. Your powder charges are bordering on being too low especially with RL 17. You are in the neighborhood of 20K psi under pmax with these loads. Barnes bullets like to be run hard when jumped.
4. Your COAL measurement of 2.98" touching the lands is for which bullet?? Each different bullet - Nosler and Barnes will have a different measurement.
5. Pick a brand of brass, I recommend Norma and stick with it. Different brands of brass have different case capacities and this can and will cause pressure differences. The Nosler brass may be similar to the Norma brass but weigh it first before combining. Its said that Norma makes Nosler brass but I'm myself am not sure of this.

Who built your gun? Have you talked to them about the problem you are having? My first impression is you are jamming the bullets into the lands each time and the swipe is from your bolt face. Is it hard to close with a loaded round? What is your freebore??

 

[fguffey]

I always read in books if you bump size a case too far it will stretch upon firing,

case head separation from too much headspace. LOL Matt

I have read that also, and then I wonder if a reloader knows the length of the chamber from the shoulder to the bolt face. And then I wonder if the reloader understands when full length sizing a case he is returning the case to minimum length. I also wonder if the reloader understands the die is designed to full length size the case back to minimum length; all of my dies have threads, threads make my dies adjustable in the press.


New factory over the counter ammo is minimum length/full length sized ammo from the shoulder of the case to the case head. Factory 30/06 ammo, by design is .005” shorter from the shoulder to the bolt face than a go-gage length chamber. Back to knowing the length of the chamber from the shoulder to the bolt face and my dies, my dies have threads, my presses have threads. I can off set the length of the chamber with the length of the case.


Exception: new factory over the counter ammo, I have no control over the clearance of the case and chamber with new ammo. But I do have an exemption on stretch; not all of my cases stretch when fired; therefore, it is assumed by most reloaders the case stretches between the case head and case body and they assume they can bump the shoulder.


I find it impossible to bump the shoulder back, I understand it sounds cool when a reloader claims he bumped the shoulder but when I move the shoulder back I upset the case body because I can not move the shoulder back with case body support. And, my cases do not have head space, if a chamber has too much head space it is because the the chamber is too long from the shoulder to the bolt face. Back to the case; I can off set the length of the chamber with the length of the case from the shoulder to the case head.


F. Guffey

 

[7Saum]

This does not have anything to do with your case head swipes but let me give you a bit of advise when it comes to your reloads.
1. Barnes LRX bullets need to jump. It appears you have them seated too close to the lands as I read it. Start at .040-.050" jump and then test seating deeper from there. This can be very dangerous if not done right. Solids like the Barnes LRX do not obdurate like cup and core bullets and need to jump to prevent pressure spikes.
2. Clean your bore before testing bullets with different jackets. Nosler jackets are harder and copper deposits left in the bore will tear the softer Barnes bullets.
3. Your powder charges are bordering on being too low especially with RL 17. You are in the neighborhood of 20K psi under pmax with these loads. Barnes bullets like to be run hard when jumped.
4. Your COAL measurement of 2.98" touching the lands is for which bullet?? Each different bullet - Nosler and Barnes will have a different measurement.
5. Pick a brand of brass, I recommend Norma and stick with it. Different brands of brass have different case capacities and this can and will cause pressure differences. The Nosler brass may be similar to the Norma brass but weigh it first before combining. Its said that Norma makes Nosler brass but I'm myself am not sure of this.

Who built your gun? Have you talked to them about the problem you are having? My first impression is you are jamming the bullets into the lands each time and the swipe is from your bolt face. Is it hard to close with a loaded round? What is your freebore??

Hi,
Thanx for all the info,when loading the Lrx I had 2.92 so it was .60 thou off the lands,every time I use a different bullet I clean the barrel like u said,I had Downrange Precision build my gun,I was informed that he is having personal issues,so it is impossible to get ahold of him,that's why I am having such an issue,I would have gone right to him but unable to...I am trying the 162 ELD-X with 62 grains of RL 26 2.94 OAL, which is .30thou off the lands,3000 fps and still getting light ejector marks on the case head..but that's it,primer looks good and no sticky bolt....So I think I might have to find another Smith to look at my gunit seems it doesn't matter what I load light or medium,seating depth,still have a ejector marks..
Thanx..

 

[7Saum]

This does not have anything to do with your case head swipes but let me give you a bit of advise when it comes to your reloads.
1. Barnes LRX bullets need to jump. It appears you have them seated too close to the lands as I read it. Start at .040-.050" jump and then test seating deeper from there. This can be very dangerous if not done right. Solids like the Barnes LRX do not obdurate like cup and core bullets and need to jump to prevent pressure spikes.
2. Clean your bore before testing bullets with different jackets. Nosler jackets are harder and copper deposits left in the bore will tear the softer Barnes bullets.
3. Your powder charges are bordering on being too low especially with RL 17. You are in the neighborhood of 20K psi under pmax with these loads. Barnes bullets like to be run hard when jumped.
4. Your COAL measurement of 2.98" touching the lands is for which bullet?? Each different bullet - Nosler and Barnes will have a different measurement.
5. Pick a brand of brass, I recommend Norma and stick with it. Different brands of brass have different case capacities and this can and will cause pressure differences. The Nosler brass may be similar to the Norma brass but weigh it first before combining. Its said that Norma makes Nosler brass but I'm myself am not sure of this.

Who built your gun? Have you talked to them about the problem you are having? My first impression is you are jamming the bullets into the lands each time and the swipe is from your bolt face. Is it hard to close with a loaded round? What is your freebore??

Do you have any suggestions on a load with 145LRX and RL17,you were saying that my load is to low,but when I see ejector marks I'm nervous to add more powder...not sure what to do...I will make sure to give it a .40-.50 thou jump..

Thanx Terry

 

[rifleman700]

Hi,
Thanx for all the info,when loading the Lrx I had 2.92 so it was .60 thou off the lands,every time I use a different bullet I clean the barrel like u said,I had Downrange Precision build my gun,I was informed that he is having personal issues,so it is impossible to get ahold of him,that's why I am having such an issue,I would have gone right to him but unable to...I am trying the 162 ELD-X with 62 grains of RL 26 2.94 OAL, which is .30thou off the lands,3000 fps and still getting light ejector marks on the case head..but that's it,primer looks good and no sticky bolt....So I think I might have to find another Smith to look at my gunit seems it doesn't matter what I load light or medium,seating depth,still have a ejector marks..
Thanx..

Try something. Take a loaded round and chamber it closing the bolt. Now open and eject cartridge and see if swipe mark is there. Sounds like a FP spring issue.

 

[rifleman700]

Do you have any suggestions on a load with 145LRX and RL17,you were saying that my load is to low,but when I see ejector marks I'm nervous to add more powder...not sure what to do...I will make sure to give it a .40-.50 thou jump..

Thanx Terry

Can you post a pic of a fired round?

 

[7Saum]

Can you post a pic of a fired round?

Can you post a pic of a fired round?

This is once fired norma brass with 62gr RL 26 with 162 ELD-X, 2.94O.A.L which is 30 thou off the lands,according to my buddies QL Program 62.5 grains of RL26 is 58,000 psi so if I'm correct I should not see any pressure signs.. (Is that right or No?)
Thanx Terry

 

[rifleman700]

I'm not seeing a distinct pressure swipe. I will try to find a picture of a pressure swipe for comparison. I am still thinking your bolt face is doing this when closing the bolt - cock on close.

I agree with your QL prediction, it should be plenty safe.

 

[rifleman700]

Ok, when I blow up the picture for my old eyes I see a very distinct ejector mark which I would think would be a headspace issue. Try measuring a fired case in all of the critical areas and compare it to a new case.

 

[7Saum]

Ok, when I blow up the picture for my old eyes I see a very distinct ejector mark which I would think would be a headspace issue. Try measuring a fired case in all of the critical areas and compare it to a new case.

Hi,
So I have been thinking,the only thing it could be in my opinon is head space (please tell me if I'm off track or wrong)but if all my loads are light-med depending on the powder of course,and after the first fireing I only neck size the brass,(now it has expanded to the size of my chamber),if I put another load in it and fire it and it still makes a ejector mark,it has to be a HeadSpace Issue!! Does that sound right or no?
Thanx Terry

 

[savagedasher]

Hi,
So I have been thinking,the only thing it could be in my opinon is head space (please tell me if I'm off track or wrong)but if all my loads are light-med depending on the powder of course,and after the first fireing I only neck size the brass,(now it has expanded to the size of my chamber),if I put another load in it and fire it and it still makes a ejector mark,it has to be a HeadSpace Issue!! Does that sound right or no?
Thanx Terry

Could be the head space of the chamber with the brass your using. All my guns are chamber long . But that is my choice.
I get the same signs if I don't jam the bullet . After the first fireing it is fine . Just don't move the shoulder back to far . Larry

 

[Preacher]

ANY time! you leave ejector marks on a case head it is high pressure..........