Reloading for new gun, cases hard to chamber

[Rifleman513]

So just finished a few frustrating hours at the reloading bench. I started reloading about a year and a half ago and have loaded for most of my rifles with great success and little trouble... until tonight.

A few years ago my dad purchased a used rifle chambered in 375 black mesa express. He got a set of dies and about 80 pieces of brass with it. He stuck it in the safe and hadn't messed with it till recently. He stuck a scope on it and dropped it off with all the components awhile back so I could work up a load for it, as he doesn't reload.

I trimmed all the cases to spec, tumbled and resized. Max COAL is 3.6, so I seated the first few rounds to 3.95. I decided to check to make sure they would chamber and this is when it got complicated. Some of the rounds would chamber as usual with no issue. With some of the rounds I could not even close the bolt. I rechecked OAL length to ensure bullets had been seated properly, which they all were. Next I decided to try and chamber some of the empty primed cases and had the same results. Some of the cases would chamber no problem and then some I could not even close the bolt. He had about 10 rounds left that the previous owner had loaded so I tried them. All of these would chamber but some were pretty hard to close the bolt.

I've never encountered anything like this till today. I took the expander out of the sizing die and cleaned the inside as best I could. I measured with a caliper the cases that would chamber easy and those that would not and could not find any noticeable difference that I could measure. The only thing I thought I may try was to try and trim them a bit shorter and see if that would help but I'm not sure if that is even part of the issue?

I'm kind of at a loss here on what to do. Any help would be appreciated if any of you have any advice or a solution to remedy this problem. Thanks in advance.

 

[bigedp51]

If you do not have a Hornady cartridge case headspace gauge I would buy one and make sure your bumping the shoulder back far enough.

The Hornady gauge is more accurate than Wilson type case gauges and all you do is measure a fired case against a resized case.

 

[rcoody]

If you do not have a Hornady cartridge case headspace gauge I would buy one and make sure your bumping the shoulder back far enough.

The Hornady gauge is more accurate than Wilson type case gauges and all you do is measure a fired case against a resized case.

yep

I would say the shoulder of the case needs to be bumped back a little more. How do you have your die set up. Screwed all the way down to the shellholder and a quarter turn more?

the hornady headspace gauge will get you that optimum 1.5 thousands shoulder bump but if you still have a problem with the die screwed all the way down to the shellholder there may be another problem.

 

[just country]

morning is this a magnum style case. does the case have a magnum ring

around the base of the cartridge?? if so the base of the cartridge will have to b

resized. the resized die is sold by. I use this on my 6.5 Mag. 300WM 257 Wbee and a

few more.lightbulb

WWWLarryWillis.Com
407-695-2685

 

[Rich Coyle]

Rifleman513,

If you have calipers you need to get something like one of he guys shows on his calipers that fits over the neck and maybe half way down the shoulder. What this allows you to measure is the distance from the shoulder to the bottom of the case. I have the same problem on one of my rifles. All I do is adjust the die and size each case individually. It takes patients, but it works. I have discovered 1/2 a thousandths makes a difference between easy bolt closing and a little sticky bolt closing. One and a half thousandths too long and it won't close without a lot of pressure. I like the bolt to close like there is no case in the chamber, but knowing if it was .001" longer it would require effort.

I had to turn a few thousandths off the bottom of the die to solve the problem. If you don't have a lathe but do have a grinder you can use it. I don't recommend the grinder unless you have lots of experience grinding lots of intricate details. You sure don't want to grind the die crooked.

 

[TOM H]

So just finished a few frustrating hours at the reloading bench. I started reloading about a year and a half ago and have loaded for most of my rifles with great success and little trouble... until tonight.

A few years ago my dad purchased a used rifle chambered in 375 black mesa express. He got a set of dies and about 80 pieces of brass with it. He stuck it in the safe and hadn't messed with it till recently. He stuck a scope on it and dropped it off with all the components awhile back so I could work up a load for it, as he doesn't reload.

I trimmed all the cases to spec, tumbled and resized. Max COAL is 3.6, so I seated the first few rounds to 3.95. I decided to check to make sure they would chamber and this is when it got complicated. Some of the rounds would chamber as usual with no issue. With some of the rounds I could not even close the bolt. I rechecked OAL length to ensure bullets had been seated properly, which they all were. Next I decided to try and chamber some of the empty primed cases and had the same results. Some of the cases would chamber no problem and then some I could not even close the bolt. He had about 10 rounds left that the previous owner had loaded so I tried them. All of these would chamber but some were pretty hard to close the bolt.

I've never encountered anything like this till today. I took the expander out of the sizing die and cleaned the inside as best I could. I measured with a caliper the cases that would chamber easy and those that would not and could not find any noticeable difference that I could measure. The only thing I thought I may try was to try and trim them a bit shorter and see if that would help but I'm not sure if that is even part of the issue?

I'm kind of at a loss here on what to do. Any help would be appreciated if any of you have any advice or a solution to remedy this problem. Thanks in advance.

I'm not sure if Black Mesa still in business and since you didn't mention getting form die I'm assume your using their brass and they more than likely chambered that rifle.

Maybe some of that brass wasn't shot in that rifle, who knows for sure how it was loaded.

That case is formed from 404 Jeffery from what I remember and you might want to form some new cases and start over working up loads for it.

I'd get hold of Black Mesa and get form die or who ever made those dies might be one that made form die. You might be able to get reamer print also.

 

[toliver]

I'm not sure about your numbers. You said max coal is 3.6 and you loaded 3.95. I dont load for that or have a manual handy but it sounds from your numbers that your .35 to long.

 

[Rifleman513]

Okay so I think I have the problem solved. I checked over lunch and I set the die up the same way I had all my others 1/8 to 1/4 turn further into the press per the RCBS instructions. I typically try to split this in the middle and has worked for all my other dies. This one however took more than the 1/4 turn to get it set right. I sized a scrap case until it chambered as it should. I guess being a custom cut chamber and die set they may be a little more finicky than the other factory calibers I reload for.

As far as getting info from BM it has been a dead end for about 5 years. It started out that brass was only 2-3 months on backorder which has now turned into 5+ years and he still has never got any brass out. We did hear from another guy that 300 RUM brass can be necked up and resized to form the 375 BME brass. This might be something we will have to work into if he decides to keep it in the future.

Thanks for the input.