Tough on brass

[skyfish]

Finally fired my Grendel. 18" with mid length gas system. It is a little hard on the brass. After break in, I removed a round that was chambered from mag when cycled normal. It had a fairly large dent in the shoulder. The "17" round mag is worse than the "26" mag. I don't have a 10. These are all factory Hornady. They remove a little hard, but I think that may be remedied with later lots. My AA(Lapua) ammo chambers easier and extracts(without firing) much easier.

I'm more concerned with the dent going into the chamber.







Also, from the pics, you can see the rings on fired brass. The brass is on the verge of being oversized. I took one and ran through the reloading die, ejects much easier after adjusting die.

[Hoot]

Do you have a caliper to measure the COL? Do you have some rounds left that have not been chambered? Measure the COL of the cartridge in the first picture versus some that were never chambered. It looks like the bullet crept forward a little when it was chambered. Some times that can cause a cartridge to be hard to extract. Some times it can result in higher pressures when fired. Higher pressure can make the extraction cycle more violent, treating the brass roughly, not to mention the other concerns. Just an idea...

Hoot

[LR1955]

Finally fired my Grendel. 18" with mid length gas system. It is a little hard on the brass. After break in, I removed a round that was chambered from mag when cycled normal. It had a fairly large dent in the shoulder. The "17" round mag is worse than the "26" mag. I don't have a 10. These are all factory Hornady. They remove a little hard, but I think that may be remedied with later lots. My AA(Lapua) ammo chambers easier and extracts(without firing) much easier.

I'm more concerned with the dent going into the chamber.







Also, from the pics, you can see the rings on fired brass. The brass is on the verge of being oversized. I took one and ran through the reloading die, ejects much easier after adjusting die.

SF:

Two things in my opinion. The chamber wasn't cut well enough and your magazines are typical CP magazines.

If those marks on the brass are really rings. I mean you can feel a raised ring or cut around the brass, you need to get hold of who ever made the rifle and have him fix it (new barrel). If it is just a marking, I probably wouldn't sweat it.

Reference your chamber. From what I understand, Grendel chambers are more on the line of a service chamber than a match chamber so take that into consideration if you think the brass is being blown out too much. However, given the rings that are appearing on firing, could well be the chamber is oversize for some reason. Most certainly that isn't good for long brass life and at a dollar a piece for brass I wouldn't be happy.

CP magazines suck. End of story. Sure, they will replace mags that don't work without question but that isn't an excuse for not making them well in the first place.

What is happening causing that dent on the shoulder is self evident. The cartridge is getting slammed into a sharp edge of the barrel extension and is getting dented. That must be eliminated or your will have malfunctions and destroy your brass. My guess is that your 17 round magazine, when loaded, is orienting the bullets outwards and probably downwards in the magazine when it should orient them towards the middle and upwards so the cartridge is already oriented towards the center of the bore when it is feeding.

Guys on the last forum had pages of instructions on what to bend on the CP magazines in order for them to work. I can't recall the entire process as the magazines have so many problems due to poor QC and manufacture that anything goes with them. It is funny but I have one CP magazine that is so out of spec, when you look at it from the top down it is shaped like a parallelogram. It works! I think it is because due to it's parallelogram shape, it jams itself into the mag well and sticks in a very high position so the bullets don't nose dive. We had major problems with their magazines nose diving bullets at one time.

I would care more about the chamber than poor quality CP mags.

LR1955

[mlmiller1]

LR1955, Is there an option instead of CP mags?

MLM

[LRS_Ranger]

You could try some Alexander Arms mags and see if that makes a difference..

[mlmiller1]

Aren't the AA mags made by C products?

MLM

[Bill Alexander]

The dent on the shoulder is from the back of the bolt lug passing over the cartridge as the rifle extracts.

17 round magazines do not work correctly. We do not list them.

CP magazines have improved considerably over time. That is not to say they are perfect but the error rate has fallen.

Bill Alexander

[longdayjake]

C product mags and AA mags are the same.

[skyfish]

Yes the 17 round mag swells slightly in the middle when loaded, the tip of the bullets were slightly orientated outward. The brass was not dented when I used the 26 round AA mags, or only very slightly. Both mags were only loaded with 3-4 rounds.

You can see rings that match the fired brass in the chamber, I will see if they can be felt or not tomorrow. New, unprimed and unloaded Hornady brass is even hard to extract. It needs sized first. I have a case of AA(Lapua) 123gr that I have chambered(not fired) that extracts easily. I have only fired this rifle 15 times, the first 5 were all singles, but were loaded from mag. I have only fired one three round group after two foulers. Shoots very well with factory Hornady.

Edit: I ordered two 10rd mags from AA yesterday, will try and shoot next week. This thing called work getting in the way. On a side note, 65 round mag, sounds interesting, even if only for a novelty.

[bucktact6.5]

I ran into the same problem with Hornady brass. The fix for me was to crank down on my sizing die and really get down on the small base.

[McCoy]

Anyone have an answer as to why the mags actually hold 1 less round than listed?

[bwaites]

Generally that happens because springs are slightly longer than spec, or the follower legs are slightly longer than spec.

CP made a few running adjustments in production, as I understand it, to improve feeding, and one of those adjustments involved slight changes to the follower, which decreased mag capacity.

[Darkop]

I ran into the same problem with Hornady brass. The fix for me was to crank down on my sizing die and really get down on the small base.

I had some trouble with Hornady brass too. I had to stone down an RCBS shell plate to move the shoulder back enough and size the brass correctly. When comparing a new factory piece of Hornady brass to a Lapua case, i could visually see a difference in the shoulder angle. I had to play with the shell plate quite a bit to get them to size correctly. This was using Hornady dies. I called Hornady and explained the problem and gave them the lot number of my unfired brass. They said there was no problem with that lot of brass. Pissed me off so I don't use Hornady brass now in my Grendel. I also switched to redding dies.

until that day,
Darkop