Pressure Signs Help Needed

[keithcandler]

Brass within a particular lot will vary as much as 6% hardness, so expect some culls when hand seating primers with some being premature loose. lapua is an exception and a few other top end brass companies.

Cull brass frequently now that you know that they are not all the same hardness, soft case heads go quickly.

 

[Tulsa Reiner]

"Dmagna, post: 1835087, member: 106055"]
Also you have to know that the Nosler loaded ammo uses different brass then their brass you buy in the boxes. I don't know why they do it. But make sure you don't mix the two, they have different capacity and will mess you up bad.

That's ridiculous!

 

[wardog5]

Brass originated as Nosler Trophy Grade 160 AB factory ammo fired through the subject rifle. This is the first time it has been reloaded. So it has been fired 2x. First time as factory, and this time.

Primers don't look like excessive pressure I have several 700 Remingtons they all crater just like those shown if bolt lift is easy i doubt you'll have a problem unless you have other signs we can't see ... do they group ok ?

 

[wardog5]

Type S FL dies with .309 neck bushing

did you skim trim the necks ?

 

[MTGEEZER]

did you skim trim the necks ?

TO Sam Summey: re: "roughing up the chamber" response to ROOK57. I have read this thread with great interest as I have a CA Mesa in 6.5Prc and experience pressure signs long before reaching the lawyer load max. loads. I full length resize using Hornady Match Grade dies and use One Shot case lube and wipe off with a cotton towel when done. My pressure signs include cratered, flattened primers and visible ejector imprints on the case base. I am going to re-clean my chamber and clean my prepped cases with an acetone fingernail polish remover and do another pressure test workup. If my problems persist, how would one go about "roughing up the chamber walls" without damaging the chamber? PS: I very carefully set my sizing die so as not to bump the shoulder too much but was only going by feel as I do not have the tools to actually measure the bump. I love my Mesa and the cartridge but don't feel like I'm reaching it's full potential. Any help (from anyone) would be greatly appreciated!!! MTGEEZER

 

[Blackhawk]

Both your cartridges show signs of extruded or cratering of the primers plus they also seem flattened out which are signs of overpressure. Here is a link to a good article on analyzing pressure signs.

MassReloading Home

Just looking at the case heads. The second one shows a slight indication on the case head ,which usually means that the cartridge case is being slammed back into the bolt face. Couple that with the primer being slightly flattened indicates you you are on the threshold of exhibiting the classic signs of over pressure. If I were you I would back off at least 10 precent on your powder and then using your 2 best friends your chrono,and the latter test determine your E.S.& S.D. Once you have established this as a baseline you can work up to your most accurate load, assuming that you have already established the optimum seating depth for your bullet(known as the jump factor). Again by using a simple test with chronograph determine your best E.S. & S.D. Please don't be fooled by the fastest MV, but rather work with your chronograph. If it is accurate it will serve you well and guide you into the best possible combination of powder, case, and bullet for your weapon of choice.

 

[jebel]

If my problems persist, how would one go about "roughing up the chamber walls" without damaging the chamber?

You're doing everything just fine. Ensure your chamber is clean and dry by swabbing it with some sort of degreaser before shooting, as you've suggested. That's all the "roughing up" you need.

 

[Lenny Foffa]

All other possibilities aside ,Is it possible you cases might be a few thousands too long. the edge of the neck biting into, the bullet, when you close the bolt. Perhaps a close examination of a few complete unfired rounds after you close the bolt , may offer a clue.

 

[Huntz]

A few things I have learned.The advice you get on the internet about reloading is worth exactly what you paid for it.Nosler uses pressure reading equipment for checking the loads they print to verify they are safe.Can you load higher then those recommended loads and get away with it.Sure you can ,but visual marks on the case mean nothing as far as a real pressure indicator.Once visual indicators show up you could already be at 75,000 PSI.If you want more speed,go to a larger case.You can get more speed with normal pressure that way.Overloading can set back your bolt,stretch your action or blow it up,just sayin,Huntz

 

[MTGEEZER]

A few things I have learned.The advice you get on the internet about reloading is worth exactly what you paid for it.Nosler uses pressure reading equipment for checking the loads they print to verify they are safe.Can you load higher then those recommended loads and get away with it.Sure you can ,but visual marks on the case mean nothing as far as a real pressure indicator.Once visual indicators show up you could already be at 75,000 PSI.If you want more speed,go to a larger case.You can get more speed with normal pressure that way.Overloading can set back your bolt,stretch your action or blow it up,just sayin,Huntz

Thank you, jebel, Lenny, and Huntz! I have degreased the cases and chamber, inspected loaded rounds before and after chambering and even re-measured loaded cases for length (everything looked good and the loaded case length is .010 less than the max. case length of 2.030). Still looking for clues! As for the ole interweb load stuff, you are exactly right, Huntz. I only use published data, start low and work up using my Magnetospeed and visual inspection and still end up about 2 full grains or more under published load max. (I use Hornady and Gunwerks headstamped brass, which I'm told is ADG and they weigh within 2 or 3 grains of each other). Anyway, I didn't jump on the Crudmore wagon specifically because it didn't offer the gitty up and go I wanted, hence the 6.5Prc. I have loaded various bullets and weights by Hornady, Sierra, Berger, Hammers, and now Barnes(127LRX). Still feel like there's something I'm doing wrong. I have learned so much from the people on this forum; I thank you all! Great day to all!

 

[JTB]

You're doing everything just fine. Ensure your chamber is clean and dry by swabbing it with some sort of degreaser before shooting, as you've suggested. That's all the "roughing up" you need.

Agree. Would not "rough-up" the chamber. I really don't see a reason to be overly concerned with the brass you pictured. If you start to experience heavy bolt lift back off. There are too many reasons for primer cratering and ejector marks to attribute it solely to excessive pressure (relatively high would be a better descriptor). I have seen more problems from rough chambers than from smooth chambers. If it is too rough the brass will adhere to the chamber wall upon firing firing and will stretch the brass just above the head as it presses against the bolt face, resulting in very short brass life. I always lightly finish chambers with a new sheet of 1000 grit paper and seems to work well.

 

[MTGEEZER]

Agree. Would not "rough-up" the chamber. I really don't see a reason to be overly concerned with the brass you pictured. If you start to experience heavy bolt lift back off. There are too many reasons for primer cratering and ejector marks to attribute it solely to excessive pressure (relatively high would be a better descriptor). I have seen more problems from rough chambers than from smooth chambers. If it is too rough the brass will adhere to the chamber wall upon firing firing and will stretch the brass just above the head as it presses against the bolt face, resulting in very short brass life. I always lightly finish chambers with a new sheet of 1000 grit paper and seems to work well.

Thank you, JTB. I actually saw one post on here (different thread) where someone suggested using steel wool on the chamber and I thought that just can't be right! The load I'm most interested in now is with the 127gr. LRX doing 3100 in front of RL26 and printing .5 inch @100 yards. I have another batch loaded up now and waiting for warmer weather and less(much less!) wind to see if it's repeatable and how it does at distance. Hopefully, I have stumbled on a good node (have nowhere to do a ladder test) as 3100 is decent speed and what I want is accuracy and repeatability. Thank you,too, to ROOK 57 for starting this topic and allowing me to get some thoughts regarding my problem! God Bless you All!

 

[John Klingenberg]

This is what I look for. The 284 has started to flatten at the edges whereas the new primer has a nice round edge.

 

[WYO300RUM]

Thank you, jebel, Lenny, and Huntz! I have degreased the cases and chamber, inspected loaded rounds before and after chambering and even re-measured loaded cases for length (everything looked good and the loaded case length is .010 less than the max. case length of 2.030). Still looking for clues! As for the ole interweb load stuff, you are exactly right, Huntz. I only use published data, start low and work up using my Magnetospeed and visual inspection and still end up about 2 full grains or more under published load max. (I use Hornady and Gunwerks headstamped brass, which I'm told is ADG and they weigh within 2 or 3 grains of each other). Anyway, I didn't jump on the Crudmore wagon specifically because it didn't offer the gitty up and go I wanted, hence the 6.5Prc. I have loaded various bullets and weights by Hornady, Sierra, Berger, Hammers, and now Barnes(127LRX). Still feel like there's something I'm doing wrong. I have learned so much from the people on this forum; I thank you all! Great day to all!

Stick with ADG/GunWerks. Just weighed 50 Hornady brass in 6.5 PRC. varies up to 4 grains. 50 ADG and GunWerks only varies 1 grain at most . Also weighed 100 Lapua and 50 Hornady 6.5x284 cases. Same thing. 1 grain and 4 grains. 100 GunWerks and 50 ADG 300 RUM. 1 grain difference. Rem brass 2 grains. I know what I'm sticking with.