Testing the shoulder/headspace issue theory

[callen3615]

So the conscience is that my reloads are misfiring due to the shoulder being bumped back too much. I had some free time before work today and I though I would test some things out. Feel free to correct me at anytime because I dont know what Im doing. lol

Anyway. I got 9 pieces of shot brass. I deprimed them and then began the resizing process. For the first 3 I hammered them very aggressively into the resizing die with a rubber mallet. They are probably 1/16th of an inch below the surface of the resizing die. For the next 3 I hammered them until they were flush with the bottom of the die. For the last 3 I left them about 1/8th of an inch out of the die. Then I primed all of them and went to test them.

My thinking here is that if I am bumping the shoulder too much when I hammer the cases into the die that the first 3 shouldnt go off at all, I really dont know what to expect for the next 6. I checked the OAL of the cases too, all were sufficiently cut (2.020-2.040).

So I go outside and ever single primed piece of brass fires. Now I confused, am I missing something here?

 

[callen3615]

Re: Testing the shoulder/headspace issue theory

This is the thread I am referring to.

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2458236#Post2458236

 

[nfoley]

Re: Testing the shoulder/headspace issue theory

Did you change anything with regard to seating primers? I read your original post and was thinking initially your problem was a primer seating issue. Also, your experiment may not have had a large enough sample size to detect the problem if it is an uncommon one. Try doing the same thing with 20 of each instead of 3. Good luck.

 

[callen3615]

Re: Testing the shoulder/headspace issue theory

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: nfoley</div><div class="ubbcode-body">Did you change anything with regard to seating primers? I read your original post and was thinking initially your problem was a primer seating issue. Also, your experiment may not have had a large enough sample size to detect the problem if it is an uncommon one. Try doing the same thing with 20 of each instead of 3. Good luck. </div></div>

Nope. seated the exact same way. I know the sample is small, I may try it large scale later.

 

[gcoulsey]

Re: Testing the shoulder/headspace issue theory

Be careful there mate, 1/16th shorter, 1/8th longer,
Your making some BIG adjustments there.. And will have various effects on the pressures of your load.

 

[callen3615]

Re: Testing the shoulder/headspace issue theory

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gfunkUK</div><div class="ubbcode-body">Be careful there mate, 1/16th shorter, 1/8th longer,
Your making some BIG adjustments there.. And will have various effects on the pressures of your load. </div></div>

These arent loaded rounds. Just primers. Im trying to see if I bump the shoulder alot if the primer will still go off.

 

[Notso]

Re: Testing the shoulder/headspace issue theory

Am I missing something here or does the "primer going off" have absolutely ZERO do do with HS or resizing amount????

IOW, I could saw off the entire case below the shoulder and it should still set the primer off. Right?

 

[callen3615]

Re: Testing the shoulder/headspace issue theory

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Notso</div><div class="ubbcode-body">Am I missing something here or does the "primer going off" have absolutely ZERO do do with HS or resizing amount????

IOW, I could saw off the entire case below the shoulder and it should still set the primer off. Right? </div></div>

You might be missing something. I was lead to believe that if a case shoulder is bumped too much the firing pin will just push the case further into the chamber and not set the primer off.

 

[Notso]

Re: Testing the shoulder/headspace issue theory

Mmmmm, I hadn't thought of that. But how do you explain the folks who make wildcat cartridges from brass with shoulders way shorter than the final cartridge will be after fire-forming?

 

[callen3615]

Re: Testing the shoulder/headspace issue theory

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Notso</div><div class="ubbcode-body">Mmmmm, I hadn't thought of that. But how do you explain the folks who make wildcat cartridges from brass with shoulders way shorter than the final cartridge will be after fire-forming? </div></div>

Hell I dont know. I didnt realize the aforementioned head space misfire issue until about 10 hours ago. lol

 

[gcoulsey]

Re: Testing the shoulder/headspace issue theory

Forming wildcats is not something I have ever done,
But I know one method of fireforming brass is to load the bullets long, jammed into the lands.. This would keep the brass from moving away from the firing too much. Just a thought.

Capt.obvious, empty cases with primers only, good call,
But not 'quite' comparing apples with apples.
IF we're assuming the problem is too much headspace, then only the x3 shortest rounds in your test had a chance of not firing..

As said above, try a few more for a fairer test.

It's difficult determining meaningful results with such a method of sizing/testing, but I understand it's all you have to go on at the moment.

Stay safe

 

[Tripwire]

Re: Testing the shoulder/headspace issue theory

It was my best guess given the entire scope of the info you divulged yesterday...I gave up those loaders a LONG time ago despite never experiencing the problem you are having.

If you find a press to load with I'm betting a lot of your worries just go away.....

 

[Notso]

Re: Testing the shoulder/headspace issue theory

to the OP.... one other thing to consider for someone trying to save some money is you don't need a fancy headspace measuring tool. Here's an easy way to measure headspace from a fired round to a resized round so you can tell how much you're bumping the shoulder back:

Find an empty .40 S&W case - knock out the primer. Take the .40 case and put it on top of the neck of a deprimed and fired (IN YOUR RIFLE) and measure the overall length. The mouth of the .40 case should be almost perfectly at the shoulder datum point. Write that number down. Do several for better accuracy and take an average.

THEN.... take the same .40 case and measure cases FL sized in your dies. Ideally, size them to where you were previously having problems. Subtract the resized case from the fired case size. The <span style="text-decoration: underline">difference</span> is how much you are bumping or setting back your shoulders. The actual lengths you measure are irrelevant - its just the difference in the two is all you care about. Ideally, .001-.003" is all you're seeing.

I don't know how far you'd have to bump them to get your misfire because of the primer pushing the case into the chamber theory. But this trick might be able to tell you.

Report back on what you find. And ditto to what everyone else is saying..... ditch those hammer dies and spend $50 on a used press. Its going to be less than your medical bills when your gun finally blows up in your face and you lose and eye.