Home Forums Reloading Big Game Rifles Wierd Sign of Pressure

So I have developed a load for my 7mm Rem Mag that shoots really well. I am loading about 65.5 grains of IMR7828 and a 160 Accubond. Here is what is weird:

My load, during the late summer, showed no signs of pressure. Good primer, no extraction marks or difficulty etc.

I loaned the rifle to my brother to hunt elk with this fall and they did a lot of riding on ATVs etc. with loads of dust. After getting the rifle back, I wiped everything down and cleaned the barrel good. Didn't do a lot to the chamber area, but just wiped it out good with a couple of patches and a rag.

Anyway, a couple of weeks ago, I went to the range during a snowstorm with my boy and a buddy. We shot the 7mm-08 and my buddy's rifles and then I pulled out the 7mm Rem Mag to check and make sure all was good.

I fired the first shot and it hit right where it should. I noticed that the bolt was a bit stiff. Hmmmm. I noticed that there was a shiny spot on the case head where the extractor grinded into it. I shot a few more and they were all the same.

Any ideas? I was really surprised and have not had that issue in the past. I was really surprised as I knew that higher heat of the summer can cause higher pressures, so this seemed odd because of the colder temps.

Let me know your thoughts. It is a pretty new barrel with only about 100-150 rounds through it so far. It is a 26" Shilen Match grade barrel and this load was designed specifically for this rifle. Neck sized RP brass and CCI250 primers.

Pull some of your loads and confirm the powder charge. Check your seating depth as well. I would think it would be less presure in the colder temps also. Strange.

First thing I would do is give my bro hell for bringing it back dirty...

How many loads do you have on the neck sized only brass? Maybe time to bump the shoulder back...

Everything gets harder to ignite in the winter and colder temps.

Maybe summer heat is not the only thing that causes pressures to rise?

So I decided I needed to investigate further. I found that inside the chamber area, the dust was SO thick. I had run a few patches through a bore guide but had missed how dirty it was in that area.

So, I took out the entire barreled action out of the stock and cleaned everything off really well tonight. We'll try again tomorrow and see what happens.

I did also notice that the brass was just a touch long, so I set it back with the Lee trimmer gauge and bumped the shoulder back. We'll go from here and see how it goes tomorrow.

Ill let you know.

FH

How compressed was the load?

It might have pushed the bullet out a bit. Might check your COAL's if the other things don't pan out.

Remember when ss and synthetic guns came out as a package many years ago? I know guys that hunted off atvs that took em to the car wash and sprayed them off ...outside and inside...at the end of season....I am not kidding here....this really happened!

My son has vangaurd 06 with a short throat, running maximum cartridge length leads to sticky bolt lift even with lite loads. I have to trim all the brass down to min trim length on all his reloads.

That same gun will also flatten primers after the first shot with factory loads, the firstshot on a cold chamber is always fine. I think must of been the last of line for the reamer they used in production.

If the ammo you shot was with him on those bumpy trails and roads. it is possible that some of the coating on the powder got worn off from the vibrations. The coatings on powder is a big part of what controls the burn rate, and could cause a higher pressure spike.

it was the same ammo for sure. I also wondered about the possibility of a compressed charge pushing the bullet out a little bit too. Don't remember if I had done a Factory Crimp on those loads or not. Definitely had at one point, but it is possible that I only did it on the previous load on that brass.

Fire Hawk, your mild compression should not be enought to push out the bullet. In addition, I would expect the compressed load to minimize the effects of vibration, that's assuming they are real (which I'm unsure of).

I'd pull a couple apart...check OAL, powder charge, and see if I could see any visible difference between the powder the case and canister....

I"d also check my rifle really close, especially barrel and chamber. I'd make sure everything was clean and dry, and shoot it again.

So I still had pressure signs today. Although not near as bad as the other day. Until.....I shot number 4 shot. That one the case separated just ahead of the belt.

Luckily nothing was hurt, but I have now thrown away about 100 pieces of brass and I am going to start all over. Something, somewhere went very wrong.

Crazy wierd situation, but I am not going to take anymore chances with that brass. I will buy new brass and start all over again.

FH

By chance...did the bullets bond to the case necks?
Try pushing them deeper into the case and see if they move ez or if it takes alot of effort and they sort of "crack" loose.

Definately something wierd.
If you still have these issues with new brass, it's time for a chamber cast.

Just another thought....did you change anything in the way you size your brass?

Sometimes I have factory crimped the bullets. I know that the ones I shot yesterday were not, but I don't remember if the originals had been or not.

Antelope Sniper, the only thing that I changed was I decided to do a total FL resize rather than just neck size.

I did also shoot some other loads that I had worked up previously with Nosler brass and they shot fine. No pressure signs and no shiny extraction marks.

The RP brass loads that I had tried were my staple for a long time. I had well over 100 pieces of brass that I knew were once fired, but sometime during a move, I lost track of which were once fired and the other pieces of brass I had. Totalling over 200 pieces without any question.

I threw out a bunch of brass a while back because I wasn't sure how many times it had been loaded. I am now thinking that maybe I threw out my once fired brass on accident and kept the stuff that had been shot multiple times.

Anyway, I threw out the rest of that brass. I still have about 80 pieces of Nosler brass and have just started reloading it. Some is now once fired and some is brand new.

I have about 40 pieces of once fired RP brass that was from factory ammo still in my reloading room too. I will FL resize the brass and begin load development for the same good load but backing off several grains of powder and working up to watch for signs again.

Anyway, I feel that I must have screwed something up along the way. Happy that the gun is okay and that no one got hurt.

FH

Short of a chrono you are only guessing as to what the real problems might be. Ever think that you might have a problem with soft brass or mabe chips of brass on the bolt face. Or brass needs trimming, or ???

The more I have thought about it, I really think I had brass that had been pushed hard for too many firings. When I moved, I lost track of how many firings it had had, and then made some assumptions. You know what happens when you "assume" something?

Anyway, I will start all over again using the Nosler brass and may do a few with the RP of the old load backed off a couple of grains, and see what happens. The original load was using RP brass. I have really had good luck with it for a long time too.

I spent a long time Saturday evening cleaning the rifle up really well. There was alot more copper in the barrel than I realized and so it is cleaned up good now. Bolt face looks good and clean. Extractor looks crisp.

Alabama Ed, I thought maybe the brass needed some trimming, and that is why I trimmed it all up nice a clean before that last trip to the range on Saturday. Rolled the loads on Friday evening after sizing, trimming and then chamfering the brass on Thursday evening. Same primers, same powder and same bullets. Oh well, I have learned a lesson and will assume that due to me losing track of how many times I had loaded the brass, I loaded them a few too many times and that is what caused the issues.

Also, the last two shots at the range Saturday were shot over a chronograph. 2954 fps and 2915 fps from the one that had the case separation. This from a 26" barrel. Seems a touch on the slow side for that load, but it depends on the loading manual I refer to.

FH

Fire Hawk- I think you have figured out your problem. Work hardened brass will no doubt give you fits. I would stick to 1 brand of brass for the rifle and like stated keep track of times fired. Also IMO there is no need to crimp. When you FL size are you just bumping the shoulder back .001-.002 and how are you setting up your die??

805,

In setting up my die, I have followed the "neck sizing" steps provided by Redding in their die set. Typically, adjust die to touch shell holder, back off one turn I think, then try to chamber. Adjust in as needed until the case chambers with little pressure. Or something to that affect.

When I FL resize, which I have rarely done, I follow the directions on the RCBS guide that came with the dies.

FH