necked down brass concern

[dragonlvg]

I am reloading some hunting ammo for my family and have come across a possible concern. some of the brass that was supplied appears to be necked down NATO spec 7.62x51 (loading for .243, some of the brass is marked as commercial milspec from the 60's and some is LC from same period. any ideas how much the pressure differential is/was with these things? or should i go with first impulse and scrap them from this load cycle? the primer pockets dont seem to be oversized but they pop out pretty damn easy and the case body is giving me more trouble resizing but no other visible signs of stress. I am uneasy loading these with same load due to seeing prior pressure signs(flattened primers).
opinions? only two options load and shoot or scrap pile i am not going to mess with reworking a load for them different then the main group.

 

[Short Round]

Re: necked down brass concern

A bag of winchester brass is pretty cheap.

A hodge podge of brass can be a PITA to manage. If you're using them all thrown together loaded the same I'd at least segregate them into batches.

 

[Hummer]

Re: necked down brass concern

The problem taking a LC case down to 243 is how thick the neck gets after the take down and THIS CAN GET STICKY QUICK.

LC necks are much thicker than commercial first off.
Next they vary in neckwall thickness considerably and this can get you in problems quickly.

To be safe I would get a neck turning tool and uniform the necks so that a loaded round will be the same dimension as a new factory round.

LC cases can be loaded many more times than commercial so they are worth saving. If you have loose primers (when seating) discard these cases.

If you stress relieve the necks (properly) and size them properly and insure the necks are not too big you can use these cases for years.

SAAMI drawing calls for a maximum neck dimension of .276 in a loaded round.

Fired cases should give you a measurement of .277/.278.

If you will PM me your email address I will copy and paste a SAAMI drawing for the case and chamber to you so you will know where you are.

 

[bohem]

Re: necked down brass concern

You can continue to load them per Hummer's advice. I shoot a hodge podge of brass for cheap plinker ammo in my 30-06 and it does fine. I expect MOA from it to about 400y, and by about 600 it's running 1.5 MOA.

It gets cheap milsurp bullets and I shoot it at steel plates which are much larger than 1.5 MOA (3-4 MOA).

I buy Win brass for the high quality ammo that I expect to perform submoa and hit MOA sized targets at 1000y.

 

[Fuzzball]

Re: necked down brass concern

I've reformed a lot of .038/7.72 brass (and .30-06 too) to .243. It can be done in one step but you will do better and loose fewer cases if you do it insteps. If you have or can borrow a 7-08 and/or .260 FL dies it will go better. AND it helps to anneal the necks first (correctly, and that's NOT to a red heat) too, and do it again after your final forming if you really want them to last longer.

The typical thickness increase will be about 1.27 x the original neck thickness.

It is very likely you will need to turn the finished necks a bit but that's part of why I do it; I WANT to even up my necks for better accuracy. It works too, a little bit, it's not fantastic of course.

 

[Enios]

Re: necked down brass concern

Agree with everything I've seen. I neck down 708 and 308 to 243. One thing I don't see mentioned is case weights...if you have a large variation in weight you need to separate brass. I've found as much as 20 gr difference in case weights in the 308 family and you will have to drop charges on heavies...

 

[dragonlvg]

Re: necked down brass concern

Thanks guys
In this case the extra work isn't worth it. this stuff will be loaded one more time and probably last the rest of his hunting life before I need to do it again. 1-MOA is better then he shoots most of the time. if i have enough i may work up a load for the nato stuff but at this point it is unlikely at this point, as i said this is hunting ammo not match loads. longest shots will be in the 300 range brass will be sorted into mfg batches but teh milsurp is getting pulled and shelved for now.
thanks again for the info
Hummer>
Ive got a set of SAAMI drawings already and am using them to spot check the finished rounds. Thanks for the offer though
Kevin

 

[dragonlvg]

Re: necked down brass concern

got shot results from first test batch back last night, one shooter got 2" groups the other rifle gets everything touching at 100, they like the results so gonna leave it alone. (these were out of bone stock guns from a standing position and kneeling respectively) mixed commercial brass hornady 100gr btsp 41 grains of IMR 4831 CCI Large rifle primers loaded to 2.645 OAL.