Is it possible to get ejector marks on the head of the brass without having excess pressure ? I'm working up a load for my 7mmRM and just about every load is giving an ejector mark but the primers look like they did before firing them. This is on some new reformed Winchester brass. Haven't seen them on the fire formed Remington brass, so may just be the new Winchester brass is softer ? The reason I formed the brass was to reduce the amount of initial stretch when first time fired . First time firing of the Remington factory ammo moved the shoulder forward .017 . New Winchester brass measures .022 longer after firing . My formed brass measures .002 longer after firing. I did have to turn the necks on the formed brass but I think it will help with neck tension consistency and concentricity .These ejector marks have me puzzled though. Anyone have any suggestions about this? Thanks
Pressure Signs ?
- Thread starter OLEJOE
- Start date
Yes. It can be seen on factory ammo running in the 61,000 + PSI range.
When I got this rifle, I went to the range with Hornady, Winchester and Remington factory loads. The Remington was the only one that would eject with ease. The others had to have the bolt bumped back with my hand. None of my reloads have any hard bolt lift or hard ejection. I still don’t know what was up with that.
I’ve been using Lyman data and some data someone posted with Quick Load. I started loading with Hornady 154 grn flat base bullets but I ran out of those. I ordered the ELD’s to try. I just started loading for this rifle and I’ve hunted with it for about 20 years. According to the barrel code, it was made in the early 90’s. It’s a custom shop 700 ks mountain rifle.
I tried the all copper bullets when PMC came out with them in loaded ammo but it didn’t like those at all.
I tried the all copper bullets when PMC came out with them in loaded ammo but it didn’t like those at all.
I think pressure is ok. But we can only guess without real pressure testing equipment.
Yeah and that’s a little more expensive than I want to go. I’ve been loading since 74 and I’ve never run up on this. Especially not being that far above the posted maximum and the primers looking like they do.
Dusty Stevens
Shiner
Typical for a belted magnum. They set the shoulders back a mile on them. 7mm rem mag is famous for this exact thing on factory brass
That’s why I formed the brass from 300 WM. It was fairly easy and should last. I may try to get some Hornady brass and see if it’s any better than the Winchester. I formed 100 Lapua 308 cases to 6.5 Creedmoor before Lapua came out with Creedmoor brass and it works great. I don’t shoot the 7 mag very much, just to hunt with, but it’s very gratifying to do it with ammo that you’ve rolled your self. It’s a very light weight hunting rig but the recoil is amazingly tolerable. I have a good many rifles and it is my favorite.
I’m going to back it down to 68 grns of H4831 and use that for the maximum. 66.8 grns is listed on the Quick Load print out I have for 60K PSI. 70 grns just breaks the 3000 fps barrier on my chrono. I’ve got some 7828 I’m gonna try next. I’m just confused about the ejector marks vs the appearance of the primers.
The Quick Load print out shows 66.8 grns at 3044 fps (near max) and I never got mine that high. 67 grns barely makes 2900 fps in mine.
The Quick Load print out shows 66.8 grns at 3044 fps (near max) and I never got mine that high. 67 grns barely makes 2900 fps in mine.
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Dusty Stevens
Shiner
Im not sure what youre seeing but i see very hard cup primers that have seen enough pressure to leave ejector marks. Theyve been hit so hard i can see how rough your boltface is.
I agree they look hit pretty hard to me. Could you have some carbon built up in that rifle?
No. I’m pretty sure there is no carbon buildup. I’ve cleaned the forward part of the chamber very well. I don’t have a borescope but it has been cleaned with a brush very vigorously. I clean it every 30 rounds or less. The primers don’t seat very far down in the pockets so maybe that’s why they aren’t flattening. Thanks for the help and suggestions.
I would stick with magnum primers, a little heavier cup.
I have had much better luck loading to 57-58K on Quick Load as maximum PSI, try that.
Pay attention to seating depth, that will affect pressure.
Also, in my experience Hornady brass seems a little softer than most others.
Really? The primers ‘look’ like they’ve been hit pretty hard?
Well they have!!
There is NOTHING in the system to slow a primer from hitting the boltface at EXACTLY whatever max psi is present. This is NORMAL, so are machining marks embossed onto them.
Even my 44Mag lever flows the primer ALL THE WAY into the ejector recess giving an exact mirror image of it.
This is also why a large firing pin hole or weak firing pin spring can and does pierce primers, the primer indent flows around the pin blanking the cup into the firing pin hole.
Also, a belted mag ‘balloons’ to fill the chamber at the shoulder/case, it does not stretch from the web forward on the first firing.
This is a myth.
Cheers.
Well they have!!
There is NOTHING in the system to slow a primer from hitting the boltface at EXACTLY whatever max psi is present. This is NORMAL, so are machining marks embossed onto them.
Even my 44Mag lever flows the primer ALL THE WAY into the ejector recess giving an exact mirror image of it.
This is also why a large firing pin hole or weak firing pin spring can and does pierce primers, the primer indent flows around the pin blanking the cup into the firing pin hole.
Also, a belted mag ‘balloons’ to fill the chamber at the shoulder/case, it does not stretch from the web forward on the first firing.
This is a myth.
Cheers.
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