Setting head space with loaded round?

[muleman69]

I thought I read in one of the post about a guy setting head space on loaded rounds? Is there a way to go about this? Trying to get my dies to head space .002 under fired case and noticed some of the older reloads are in excess of the fired case.

 

[memilanuk]

Probably the best way is to do as described in Wheeler Accuracy's video on YouTube. With a stripped bolt and *fired* cases, not live rounds.

Not saying there might not be a way to do what you are asking... but I for one sure as heck am not going to tell you its okay to do that sort of thing on a public forum.

 

[fguffey]

I thought I read in one of the post about a guy setting head space on loaded rounds? Is there a way to go about this? Trying to get my dies to head space .002 under fired case and noticed some of the older reloads are in excess of the fired case.

Yes he believes the case has headspace, my cases do not have head space. My cases have a length that is determined by measuring the distance from the datum/shoulder to the case head. I off the lwength of the chamber with the length of the case from the datum/shoulder to the case head.

And then there is that part about how a reloader can change the length of the case from the datum to the case head: There is a die that uses bushings for the neck and a die that sized the case body including the shoulder. In the rush to rename everything reloading the die is now called a body die.

One day a reloader screwed up and could not close the bolt on his reloads, SO, he sized the cases with a bushing die that is also called a body die.

I have misused dies in the past, I have sized 30/06 cases with 8MM/06 dies, I could say; "Think about it" The 8mm06 die will not sized the neck of the 30/06 and the 30/06 die will not size the 270 case neck. I do not recommend sizing loaded ammo.

I have sized 45ACP with a carbide die because I have a 45 ACP that does not like my reloads.

F. Guffey

 

[M-61]

My cases have a length that is determined by measuring the distance from the datum/shoulder to the case head.

That length is the headspace of the case fired in your chamber. Minus spring back etc.
If you look at a go gauge next to that fired brass.....there seems to be a similarity...no?

I do not recommend sizing loaded ammo.

I am with you on that.

 

[searcher]

Just a thought. We are under the assumption that the fired case you are looking at has expanded to the fullest diameter that it can in your chamber (less a bit of bounce-back). Usually, unless the bullet was jambed into the rifling to hold the case in the far rear position against the bolt when fired, full expansion does not take place - and often does not do so with several firings. I bring this up, as if your "older reloads" chambered properly before, and did so with no extra perceived bolt resistance, you may be setting yourself up to pushing the shoulders back further than your subject empty case might lead you to believe. Be sure to measure a BUNCH of fired cases and if you have a number that all are the SAME length (from base to shoulder)- and they are the LONGEST, those likely indicate your brass is fully expanded - and will likely provide you with a good measurement. The more that you have that are shorter than the longest, the less I'd be sure the longest are fully expanded. But to your question - it surely can be done - but in the unlikely event that a round ignited while contained in a die of any kind - think hand grenade. Semper Fi

 

[dcali]

I thought I read in one of the post about a guy setting head space on loaded rounds? Is there a way to go about this? Trying to get my dies to head space .002 under fired case and noticed some of the older reloads are in excess of the fired case.

You need to be more clear about what you want to do.

If you want to set the headspace of a chamber using a loaded round in place of a headspace gauge, then don't. Do it right with a headspace gage.

If you want to resize loaded rounds, also don't. You will probably get away with it if you try, but why be stupid? You want to find out what happens when you fire a round when it's surrounded by a sizing die or want to pry a stuck loaded round out of a sizing die? I don't.

Do things the correct way using the equipment the way it was designed to be used and you won't wind up with this sort of problem in the first place. In this case, it means firing the rounds in whatever rifle they were loaded to fit, or just pulling the bullets and starting over.

 

[Bart B.]

Usually, unless the bullet was jambed into the rifling to hold the case in the far rear position against the bolt when fired, full expansion does not take place - and often does not do so with several firings.

All my 308 Win cases sized to about .003" head clearance with full to 8% reduced charges and hard seated bullets seated into the lands fully expanded to chamber size before shrinking back a little. Evidenced by primers flush with case heads.

Starting with about 10% reduced loads, primers were out a few then several thousandths past the case head. Not enough peak pressure to push the back half of the case back until the case head stopped against the bolt face pushing the primer back in

 

[FatOldMIHunter]

I thought I read in one of the post about a guy setting head space on loaded rounds? Is there a way to go about this? Trying to get my dies to head space .002 under fired case and noticed some of the older reloads are in excess of the fired case.

Do the older reloads chamber in your rifle? If so, don't worry about it. If they don't chamber, the conventional wisdom is to dissassemble, save the charge, resize the primed case, reload. I have some 7mmRM ammo that my buddy reloaded for his rifle. He sold his rifle and then we tried the ammo in mine, but it won't chamber. The case to shoulder datum exceeds what I have learned from empty brass will chamber. Aside from making disparaging comments about his loose chamber, my options are limited to disassembly or disposal. Attempting to bump the shoulder down on live ammo just seems too risky.

 

[muleman69]

Just a thought. We are under the assumption that the fired case you are looking at has expanded to the fullest diameter that it can in your chamber (less a bit of bounce-back). Usually, unless the bullet was jambed into the rifling to hold the case in the far rear position against the bolt when fired, full expansion does not take place - and often does not do so with several firings. I bring this up, as if your "older reloads" chambered properly before, and did so with no extra perceived bolt resistance, you may be setting yourself up to pushing the shoulders back further than your subject empty case might lead you to believe. Be sure to measure a BUNCH of fired cases and if you have a number that all are the SAME length (from base to shoulder)- and they are the LONGEST, those likely indicate your brass is fully expanded - and will likely provide you with a good measurement. The more that you have that are shorter than the longest, the less I'd be sure the longest are fully expanded. But to your question - it surely can be done - but in the unlikely event that a round ignited while contained in a die of any kind - think hand grenade. Semper Fi

I here you for sure on the set back of loaded rounds, was just asking as I saw on a post somebody was headed for a match and set his back ,always wondered about it. I have been trying to find a comfortable head space and not really having any luck. My fired cases haven't told me much as they are coming out shorter than they are going in(guess the spring back is really messing me up? I will do as you suggested and go with the longest that measure the same. Semper Fi

 

[muleman69]

Do the older reloads chamber in your rifle? If so, don't worry about it. If they don't chamber, the conventional wisdom is to dissassemble, save the charge, resize the primed case, reload. I have some 7mmRM ammo that my buddy reloaded for his rifle. He sold his rifle and then we tried the ammo in mine, but it won't chamber. The case to shoulder datum exceeds what I have learned from empty brass will chamber. Aside from making disparaging comments about his loose chamber, my options are limited to disassembly or disposal. Attempting to bump the shoulder down on live ammo just seems too risky.

Yes they do chamber, just got wondering about correct head space. Thanks

 

[Bart B.]

My fired cases haven't told me much as they are coming out shorter than they are going in(guess the spring back is really messing me up?

Firing pin impact often sets case shoulders back a couple thousandths or more. Reduced loads don't always have enough peak pressure to fully expand the case.

 

[muleman69]

Firing pin impact often sets case shoulders back a couple thousandths or more. Reduced loads don't always have enough peak pressure to fully expand the case.

Great info. I will fire some hotter loads (safe loads) and check the results. I'm probably over thinking again. Looks like as long as my bolt closes with mild or less resistance I should not be worrying about it. Thanks

 

[Bart B.]

Looks like as long as my bolt closes with mild or less resistance I should not be worrying about it.

No resistance is best. That let's the bolt head go in battery repeatable from shot to shot. Makes groups 1/8 to 1/4 MOA or more smaller.

 

[fguffey]

My fired cases haven't told me much as they are coming out shorter than they are going in(guess the spring back is really messing me up? I will do as you suggested and go with the longest that measure the same. Semper Fi

they are coming out shorter than they are going in

The above quote is 'what is' messing you up. For years and years I have said reloaders do not understand what happens to the case between pulling the trigger and the bullet leaving the barrel and part of the problem is the infatuation they have with "HEAD SPACE". You claim the case gets shorter, that is one of those things that leaves me to believe reloading is not fair because my cases get shorter; SHORTER WHERE! ? I have cases that shorten .045" from the end of the neck to the case head, at the same time the same case gets longer from the shoulder of the case to the case head and then there is the miracle, my shoulders do not move.

Why do my cases get shorter when fired? My cases form to the chamber, my cases expand, my cases form to the shoulder of the chamber and my necks expand. When my cases expand the neck is pulled back when the case body forms to the chamber; the neck shortens when the neck is pulled back because part of the neck becomes part of the shoulder.

The case that shortens .045" is formed in a wildcat type chamber; the neck of that case after forming is .217" long from the neck/shoulder juncture to the end of the neck. When I eject that case after firing it is formed. I do not use cute loads, methods and or techniques. I fire the case and then measure, I do not find it necessary to ware the case out forming it. I measure the length of the chamber first from the shoulder/datum to the bolt face in thousandths.

And if I necked a 30/06 case neck up I would not use an 8MM die, I would use a 338/06 or 35 Whelen sizing die. When I neck my 30/06 cases up to 35 Whelen my cases shorten .020"+. again, when I neck up my cases they shorten from the end of the neck to case head, the length of the case from the datum to the case head does not shorten unless I crush the case.

F. Guffey

 

[Bart B.]

One other thing....

Fired cases usually have shorter length head to mouth than before being shot. After full length sizing, they grow back that much plus several ten-thousandths inch more.

This is why cases need trimmed back after a few to several reloads.

 

[searcher]

muleman69; You mentioned you heard of another shooter "setting his back" prior to a match. It may be possible that you misheard what the shooter was doing, though please pardon me if that is not the case. It is VERY common for those who load their ammo well prior (like weeks or more) to a match to load it with the bullet protruding a few thousandths longer than what it will be when shot, then, just prior to the match, they will set the BULLET back to the desired final overall loaded cartridge length. This is done to break the galvanic action or "cold weld" that is caused by the dissimilar metals of the jacket and neck. The cold weld can create uneven bullet release. "Setting them back" breaks that weld to again allow more uniform bullet release. Setting back the shoulders on loaded ammo is NOT the norm.