Hi, several months ago I bought a nice vintage Parker Hale cal .375 HH rifle in good conditions. Since, I shot only 10 Federal original cartridges and about 20 reloaded by me. While I don't remember anything special about the original cartridges, except that they were VERY hot, the 20 that I reloaded all showed protruded spent primers; I tought that the culprit was the low pressure, since I reloaded with 73 gr of W760, behind a 270 gr Hornady SP bullet. Yesterday, I reloaded the same bullets with 75.3 gr of W760, but the problem is still there; spent cases have a good aspect, no sign of high pressure or shining rings at the base, but primers still protrude by 0.2/0.25 mm. (0.0078/0.009 "). I use FL RCBS dies that I adjusted to barely touch the shell holder. What is your opinion?

Looking at Hodgdon data 75grs is the starting load for a 270 in a 375H&H. Loadtech calls it around 56,000psi. Sounds to me like you have a chamber to the long side and your powder charge isn't hot enough to move the head back.

I never set my belted magnum dies up to kiss the holder. I set them up to just bump the shoulder. That way after the first firing they headspace on the shoulder. I've found when I bump the holder I over work the brass.

I agree with ramrod. Take one of the factory fired cases that doesn't have the primer protruding and put black marker ink on the neck and entire shoulder. Then screw your sizer dies out so there is a good gap between it and the shell holder. Resize the case and note where the die touches the case where you put the ink marker. Continue turning the die in little at a time until you just notice the putting a mark on the shoulder,preferably the part of the shoulder nearer the neck. Then try that empty case in your rifle. If the bolt closes fairly easy, you're good to go. If not turn your die in just 1/8 turn (or less) at a time until the case chambers okay.

In my opinion the only reason to have a belt on a cartridge is to head space it only if it's a straigh walled case like the 458 Winchester Magnum. They should have never put them on bottle neck cartridges and only done so, in my opinion, as a sales gimmick.

This is how I set up my sizing die for bottleneck cartridges. Works just fine on rounds like the .375 H&H.

1. Take a once fired factory round and blacken the neck and shoulders with a Magic Marker or Sharpee pen. Some people like to smoke the neck and shoulder, but I find the Magic Marker/Sharpee pen a bit better.

2. Carefully lubricate the case.

3. Loosen the lock ring on the sizing die and back off about two turns from when the die is set to touch the shell holder.

4. Size the case. Note where the marks are on the case and turn the die down about a half a turn and size again. Turn down some more, and resize again. What you are looking for is the marks on the blackening just touching the shoulder.

5. Clean the lube from the case and try it in the rifle. It may chamber just a bit on the snug side. If so, turn the die down ever so slightly, lube and size again. Wipe off the lube and try in the rifle. If it slides in as easily as a factory round, you should be good to go. If not, usually one more very slight adjustment should fix the problem.

6. Tighten the locking ring for the die and you're done. You have just set your sizing die up for a custom fit to your specific rifle, rather than a generic one size fits all guns.

Paul B.

Some good points folks! I will switch to a faster powder (Vith. N140) that can possibly push the base further back and carefully adjust the resize die.

Protruding primers on a fired case is the result of overly resized cases that were to low in pressure to stretch the case back and reseat the primer flush. Correcting the poor case-to-chamber fit will prevent it.

Screwing down a die a half turn changes it by almost .036", that's a LOT more than a small change. I suggest turning the sizer out about a quarter turn from touching the shell holder and moving it back down in increments of no more than 1/16 (.0045") at a time) until you get a slight crush fit in the chamber.