converted SRP to LRP

[misser]

had some 308 SRP brass that the primers pockets had gotten worn out . i wondered how difficult it would be to convert it to LRP . turns out it not that difficult ,thats is if ya have a smallish lathe .

 

[AJC1]

had some 308 SRP brass that the primers pockets had gotten worn out . i wondered how difficult it would be to convert it to LRP . turns out it not that difficult ,thats is if ya have a smallish lathe .

I can't believe that would be a good idea because if you over expanded small rifle primer brass by shooting overpressure I know you're going to re-engineer the case had to accept a large rifle primer. It may be physically possible to do but I wouldn't do it

 

[Legionnaire]

I was thinking along the same lines. How many loadings before you developed loose primer pockets? Have you been trimming the cases and annealing their necks? Not sure I'd want to cut new primer pockets in heavily worked brass. I'm sure it's possible, but is it worth it?

 

[misser]

ahh then to tighten a LRP pocket to hold on to a primer . does that also bother you?

 

[edwardware]

. turns out it not that difficult ,thats is if ya have a smallish lathe .

I would think that'd be fine, if somewhat time consuming. Are you reaming or single-pointing?

You should certainly check for incipient head separations if you aren't already.

 

[Legionnaire]

ahh then to tighten a LRP pocket to hold on to a primer . does that also bother you?

Doesn't bother me at all, and I've been known to do it for known softer brass. But I also know the number of firings and that the case necks have been annealed, so I'm not trying to prolong the life of brass that has become thin or brittle. Again, the question is, "Is it worth it?" In some situations, it very well might be ... perhaps to get another firing from a case in a less popular or wildcat cartridge. But .308 brass is plentiful.

My apologies if I seemed to be criticizing. My first thought was actually, "I'll bet that could be done on a Lyman Case Prep Xpress."

 

[Blue68f100]

I did that to 45acp years ago when the SP started showing up. Made a jig that fit my vice jaws on my end mill. Set the travel stop, then reamed out to proper size.

 

[AJC1]

I did that to 45acp years ago when the SP started showing up. Made a jig that fit my vice jaws on my end mill. Set the travel stop, then reamed out to proper size.

Is there a lower pressure case than 45 ACP? I could see that maybe... high pressure rifle I'd pass.

 

[Bwana John]

Real men drill them out for 209 shotgun primers.... It takes a "C" drillbit.

 

[Charlie98]

Is there a lower pressure case than 45 ACP? I could see that maybe... high pressure rifle I'd pass.

+1

I’ve had .308 rifle brass blow out on me a few times in my M1a... it was not fun. The case heads fractured and blew out the magazine. I’m a little more sensitive about case wear now, and will scrap cases that even hint at failing. Brass is a wear item...

 

[kelbro]

Do you understand that the primer pockets got larger due to case head expansion? Weakening the circumferential area at the base of the case? Not a good idea.

 

[edwardware]

Do you understand that the primer pockets got larger due to case head expansion? Weakening the circumferential area at the base of the case?

Your thinking like steel. Brass work hardens across it's nominally elastic strain range, so the case head is stiffer, and quite possibly stronger, after repeated firing and reaming to LRP, than it was originally. For certain it's stiffer and stronger than new brass with an LRP pocket.

 

[Charlie98]

so the case head is stiffer, and quite possibly stronger,

It is harder, not stiffer. Hard can also mean brittle, which is why work hardened case necks split.

 

[kelbro]

It is harder, not stiffer. Hard can also mean brittle, which is why work hardened case necks split.

Exactly. Most rifle/pistol brass that fails at the base cracks, due to brittleness.

 

[edwardware]

It is harder, not stiffer. Hard can also mean brittle, which is why work hardened case necks split.

No, it's definitely stiffer. It's also harder (which is just stiffness + strength measured at a local surface scale) that's less interesting.

And brittleness (low strain to rupture) is distinct from both stiffness (a bulk property) and hardness (a surface property). In brass, with increased stiffness you do get reduced strain to rupture (brittleness), but case heads all but never fail in rupture, almost always by straining until they leak hot gas.

Most rifle/pistol brass that fails at the base cracks, due to brittleness.

Perhaps you're referring to head separations? That's a completely distinct failure, in the body not the head, and unrelated to work-hardening or primer pockets.

 

[misser]

i have found its a good thing to use a small light to shine into each brass just to make sure the stretch mark has not happened.