Cracked Hmr Ammo Help

[Deker 3,491]

This subject really should be pinned, it comes round and round again.

 

The manufacturing process of HMR ammo is flawed, the annealing process or lack of it, leads to split cases at the neck, sometimes before, and relatively commonly after firing.

 

This is nothing to do with individual makes of ammo (many of which are made by CCI anyway), it is the manufacturing process, and as our knowledge and technology stand this cannot be solved.

 

It does not itself cause a problem in firing/accuracy/safety, although I would be much happier if it didn't happen.

 

Hang fires, no primer or powder, quality control issues, batch problems, etc., are other matters and commonly unrelated.

[Deker 3,491]

This is a well known and long established issue, this goes back to 2007. Whilst every word may not be quite 100% accurate today, the fundamental problem remains, and will remain until technology advances to solve it (don't hold your breath).

 

From Bob Palmer at Hornady, Published in Shooting UK 2007

CCI makes the cases for all the .17 HMR ammo and loads it for the different companies. When they make the cases they draw the case out to a .22mag case that has a straight wall. Then the priming compound is put in the rim of the case. The case is spun to put the primer evenly in the rim.

After the priming is complete the case mouth is reduced to the .17 calibre to hold the bullet. The reduction process, however, puts stress on the neck of the case. They obviously cannot anneal the neck of the case to relieve the stress because of the compound in the rim, so from time to time you will get a case that cracks. Some batches may produce more splits than others. The chamber pressure on .17 ammo is so low that it does not hurt the chamber on the rifle.

They have tried to anneal the cases more before it's formed to .17, but this did not eliminate the cracks altogether. If the cracks were minor I would continue to use the ammo. The cracks do not affect the accuracy of the round and the brass is not reloadable.

[Alsone 789]

One or two reports have started to surface about the odd cracked round in .17wsm as well although I haven't heard of any of the other ammo problems people have had with HMR.

 

From what Deker says it sounds very much that until they start making the cases natively in .17 rather than drawing them down, these issues may continue. Surely they can be cast with a .17 neck can't they?

[shropshire dan 467]

Ok if I have many more ill let you know Deker