.223 neck size only on a Semi?

No worries. It is just my curiosity. I don't expect a lot of movement either, or somebody must have been yelling bloody murder already.

Talking about the shoulder being bumped back, I remember there was wild debate on this forum while back. Some claimed the firing pin strike can set the shoulder back as much as 0.01". I find it difficult to accept, as the majority of the striker's energy should go to the primer, not the shoulder. But I didn't do experiment to verify either.

-TL
 
I remember there was wild debate on this forum while back. Some claimed the firing pin strike can set the shoulder back as much as 0.01".
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Yep I recall us talking about it . If memory serves , BartB was big on that theory . I actually tested that as well . I tested a Ruger American rifle and Savage model 10 both in 308 . Neither firing pins set the shoulders back . BartB later clarified he was speaking of older Mil-Surp rifles with very heavy hammer or firing pin springs and claimed he had ran his own test with said type rifles proving the theory .The fact I have no such rifle to test my self means I have no data on the theory other then the modern rifles I tested . How ever I always had respect for Bart and what he had posted here so I have no reason to doubt what he claimed . I can say the two rifles I tested did not set the shoulder back simply by being struck by the firing pin .

I'll add my test were with empty cases ( no bullet or powder ) I did use live primers though in order to get the full striking force of the firing pin .
 
BartB later clarified he was speaking of older Mil-Surp rifles with very heavy hammer or firing pin springs and claimed he had ran his own test with said type rifles proving the theory .
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I think he was talking about Mil-surp in that post, I read it a while ago. I cannot say if the firing pin sets the shoulder back, but I do have a GEW Mauser 98 action with factory spring, trigger, and pin, and that thing hits like a ball-pin hammer.....You DO NOT have to worry about light primer strikes with an old un-modified Mauser action :)
 
Shoulder setting back 0.01" means head clearance of at least that much. That is head separation within a firing or two. All my center firing rifles are milsurp, except a Remington 700. My brass last at least 15 firings. The theory doesn't make sense, at least not to me.

Anyway, not that it is important. It is a side thought.

-TL
 
Shoulder setting back 0.01" means head clearance of at least that much. That is head separation within a firing or two.
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I'm not sure I agree or may not understand what you're saying . I size my AR brass to set the shoulders back .002 to .003 . My test show the BCG slamming home sets ghose back another .001 for a total of .003 to . 004 of head clearance . I still get 7+ loadings from them .

So at least for me .004 clearance does not mean head seperation in one or two firings .
 
0.01" > 0.004"

-TL

Sorry I was in a hurry.

Your head clearance is 0.004", which is quite good for a semi auto. 10 firings shouldn't be problem.

0.01" head clearance is too much. You are lucky to get a few firings out of it.

-TL
 
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No I'm sorry , i did not recognize you wrote .010 rather then .001 . So yes you're correct ten thousandths would be way to much head clearance .

Sorry for the misunderstanding. :o

Here are some cases that had somewhere between .008 to .010 head clearance I shot . The head separation/cracking happened on the third firing .
G9JFNo.jpg
 
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I just tried that myself, about the bullet movement. 168gr bullet on 8mm Mauser. Rifle is Hakim. One round in magazine (minimum friction). No measurable change in COAL.

-TL
 
Uncle Nick and I rarely agree on anything, but this time I do. Out of thousands of M16 and M16A-1 rifles I worked on, only one fired out of battery. The operator took a lot of brass in the arm and face. Supposedly these rifles cannot fire out of battery, but this one did. The only conclusion we could come to was that it was so dirty it could not feed the cartridge far enough to lock up.

When it comes to an autoloader still having pressure when it unlocks, yes it can. That is what timing is all about. We used to bump up the bleeder valve on the 240 coax guns so far that flame came out of the bottom when it extracted. Anybody that has converted a gas operated autoloader to a different caliber can tell you how hard it is to balance it out.
 
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