NSpeziale

I bought some HSM ammo for a 7mm mag with 168gr berger and I measured the brass cases. I measured right before where the case starts to neck down to the bullet. The tolerances differed up to 0.001. Is that too much? I heard bad things about HSM being already fired brass and im nervous to fire this stuff.

Any thoughts would be great.

dylan_b

if its just 0.001 and you were using calipers, it could have been you. a machinists old rule of thumb is only to trust calipers down to 0.005 and pull out the micrometer after that. modern calipers are much more accurate then 0.001 especially if you have a good set of mitutoyo's or starret's but the average joe who hasn't had the proper training in measuring to iso standards really wont be able to use calipers with consistency down past 0.002 on anything bigger then 1'' in diameter. calipers are just not the most consistent tool in the box compared to better methods

Wayspr

I'd consider a difference of .001 to be pretty darned good.

tcshooter

Brass isn't machined, it's formed, so +/- .001" is pretty good. Even with modern machinery being what it is, I'm pretty sure you'll never see tolerances in tenths (1/10000") in cases.

Nomercy448

Back up a step. The fact that HSM is remanufactured, or rather reloaded brass, why is that a problem? HSM is typically one of the more accurate and precision loaded factory ammo available, let alone for the price. Regular brass weight, great tolerances, precise powder charges, and strict coal.

And frankly, if your factory chamber catches the difference between 0.001", then you need to send it back, as it was machined improperly. Only a custom reamer ordered for a custom rifle will cut a tight enough throat to catch that level of difference.

Sheridan

+1

I consider it far better than me !

HSM shoots better than me also !!

If I do my job it's still a heart shot........ DRT (I like that) !!!

Gunplummer

I have made a few reamers over the years and if I remember correctly, the body diameter on most case specs has a tolerance of .008. Mic some Winchester brass (Notorious for holding on the low) and then Mic some Remington and Federal brass. Use new loaded ammo, not resized brass.