Every now and then I get an ejector mark

[Ridgerunner665]

Same load, every charge weighed on a 505 scale...and every now and then (say 1 out of 10) I get an ejector mark

The load is for a 308:
168 grain Nosler C.C.
44.5 grains of RL15
Rem brass
CCI BR2 primers
2.82 OAL (I measure every one)
2,575 fps (20 inch barrel)
very accurate load

I'm quite sure that load is not all that hot (warm...yes), but I can not figure out why I get the occasional ejector mark. I do have an idea...but I thought I'd ask and see if anybody else had ever had this problem.

 

[jtoews80]

I load 180 AB's with 44.0 grains of IMR 4064, that is a max load for 4064; however it is a compressed load from 42.0 up without a drop tube. I realize you are not putting as much bullet into the case, but it could be related to compression.

CC.

 

[Ridgerunner665]

Not a bad thought...but mine is not a compressed load. It takes 45.5 grains to compress the powder with that bullet at that length.

I have had this problem with a few loads...sometimes 46 grains of RL15 will not cause ejector marks...but usually it does.

At 44.5 grains though...the primers look fine, even on the cases with the ejector marks.

 

[Guest]

I suspect you are on the edge as far as pressure goes, and you're experiencing ejector marks on the few that range up into that realm in the pressure distribution. Back off a grain or so.

 

[Ridgerunner665]

I considered that...but if I back off a grain the MV will be 2,490 fps...even factory 168 grain ammo shoots faster than that out of this gun.

I don't think pressure is the problem...I think its the brass, but I was hoping to get a confirmation that Remington brass is sometimes not so consistent...some are hard, some are soft.

Federal brass (generally accepted as being soft) will shoot that load.

 

[jtoews80]

That would be relative to case volume, if the case capacity varies by a few grains, you are bang on with that. I used to weigh my cases with a digital scale. Winchester brass weighs 156-160 grns per case and Fed ranges from 173-177grns. I'm told that this method isn't the most accurate and I've read that some people use a fine grained ball powder (that won't settle or comress) like win 748 to fill the case to the brim and then weigh it. If you see a significant volume difference that is the problem. You could check the marked cases against the unmarked ones and that should tell you. I would make sure to use a medium rate powder instead of a fine pistol powder as a safety precaution.

CC.

 

[Ol` Joe]

"I considered that...but if I back off a grain the MV will be 2,490 fps...even factory 168 grain ammo shoots faster than that out of this gun.

I don't think pressure is the problem...I think its the brass, but I was hoping to get a confirmation that Remington brass is sometimes not so consistent...some are hard, some are soft.

Federal brass (generally accepted as being soft) will shoot that load."

The factory is likely useing a different powder to get their velocities.

I tend to agree you are loading a bit on the warm side for your rifle. The Nosler #6 claims 44.0 gr of R15 is a max charge. I`d drop the powder charge or change powders if you feel the lose of 90 fps will prevent you from killing game cleanly

 

[Ridgerunner665]

Like I said...Federal brass with 44 grains of RL15 will shoot that load 60 fps faster and without pressure signs.

The only factory ammo that I shoot is Match ammo (FGMM, Hornady Match)...Match ammo is always loaded light.

It has something to do with the Remington brass...I was just seeing what kind of ideas you guys may have about what else could cause it.

I know of a few things besides pressure that will cause ejector marks (sharp edge around ejector hole in the bolt face, excessive bolt thrust from leaving lube on cases)...the problem is I don't think any of them are the problem I have.

And its not about killing game this time...its about hitting targets at 800+ yards. (speed matters...and I'm not asking for anything unreasonable)

 

[BK]

The only factory ammo that I shoot is Match ammo (FGMM, Hornady Match)...Match ammo is always loaded light.

Uh, actually Federal, at least, loads all of their .308/7.62x51 within 50 fps of each other... American Eagle 168, FGMM 168, Vital Shock GameKing/TSX/Trophy Bonded 165.

My thought is that either some of the brass is soft, or maybe the ones showing marks are heavier and therefore have less capacity.

 

[Ridgerunner665]

Its a well known fact that Federals 168 GMM load is 42.5 grains of IMR 4064. (and I agree....that its warmer than other Match loads, but still not very hot...IMR 4064 is a good powder for speed in a 308)


You may be right about the case capacity or brass hardness...its either that or my bullets are getting "setback" during recoil.

 

[JDMAG]

Its a well known fact that Federals 168 GMM load is 42.5 grains of IMR 4064. (and I agree....that its warmer than other Match loads, but still not very hot...IMR 4064 is a good powder for speed in a 308)


You may be right about the case capacity or brass hardness...its either that or my bullets are getting "setback" during recoil.

Just shoot 10 -20 rounds one at a time with out loading the mag. If it is recoil related, it shouldn't happen, as you have estimated this only happens about once every 10 rounds.

 

[elkeater2]

I over-crimped with a Lee factory crimp die in another cartridge and raised pressure for sure. Operator error.

If you're resizing a tad too much, the case can get an extra run at the boltface as the result. Seating tight to the lands with a seater that doesn't fit the bullets well can cause some variation that could make a difference.

I do think you're onto something with the Remmy brass though. I used some fine steel wool to shine the brass bases once, then resized, just so I could see the marks consistently.

Just my 2cents worth, or less......
Elkeater2

 

[JD338]

Have you tried weighing cases? Is it the same cases getting marked?
Keep in mind that different manufactures of brass have different construction, case capacity. I'm thinking the Rem case is a tad warmer than you think.

JD338

 

[Ridgerunner665]

Remington brass does not have the highest capacity...but its is pretty good.

Winchester has a bit more and Hornady Match brass is the highest capacity that I'm aware of.

Winchester brass is impossible to find these days...

 

[Ridgerunner665]

BTW...I have to wait until I get a new chrono before I can "tinker" with this anymore...but keep the ideas coming if have them.

 

[coyotetrapper]

why not use Nosler brass? It comes weight sorted and is good stuff! I use it in my .243 and 22-250.