I could have blew my gun up

I don't believe bolt lugs will give enough mechanical advantage to move a shoulder. I have no way to test that, just basing that on experience and common sense
 
Did you use a factory crimp . I had a problem with that on a 221 fire ball. For me I don't think factory crimp on rifle calibers.
 
My loading bench, doing some berger 95g vld hunting bullets with IMR 4064.
 

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Just a quick question, will an AR10 chamber brush work on a remington 700 308 chamber? or will it cause wear or damage?
Bolt action chamber brushes are not that easy to find.
 
hounddawg said:
I don't believe bolt lugs will give enough mechanical advantage to move a shoulder. I have no way to test that, just basing that on experience and common sense
Click to expand...

You need to have words with SAAMI and find a medium to have them with Julian Hatcher, then. SAAMI has rimless cases pretty consistently sized to allow up to that same 0.004" of compressed fit. As I mentioned, Hatcher reported measuring a 0.006" shortening of a 30-06 ejected live after feeding in the Enfield.

The way you can test it out is to resize a fired case in an FL or SB die just short of the shoulder of the case touching the shoulder in the die. That will increase the head-to-shoulder length by squeezing it in the opposite direction from what happens chambering a long case. Then try chambering the case.

SAAMI max cartridge head-to-shoulder datum for 243 Win: 1.634"
SAAM min headspace for 243 Win: 1.630"
 
Ever wonder why Wilson does not make inline FL sizing dies? I'll pass on the testing, I don't feel like taking a chance on galling my rifle bolt lugs
 
Unclenick said:
The brass can't expand excessively unless the steel around it has first also expanded excessively. Steel is more elastic than brass, so it can spring back more, clamping down on the expanded brass. But the steel expansion is why this is generally considered a pressure sign. Another cause of difficult bolt lift is case head brass flowing into bolt face features (around the extractor if it is not flush with bolt face or isn't a close fit, or flow into the ejector tunnel) so that the bolt is having to scrape or smear the brass flowed into those features to open. This can feel sticky and examining the brass reveals it pretty clearly.




Usually, you can. This is why, looking at the SAAMI drawings for many rounds, the maximum head-to-shoulder datum on the case is longer than the minimum chamber headspace. In the case of the 243 Win, the cartridge maximum is +0.004" over chamber minimum and is still considered compatible by SAAMI. The idea is the chamber can absorb some extra brass by virtue of being a little wider than the cartridge, so the brass between the head and shoulder can be squeezed out fatter into that gap by the bolt lugs closing.
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0.003" over saami may be possible to chamber as the chamber is slightly longer. But 0.003" longer than the actual chamber, or -0.003" negative head clearance, is not. The OP is referencing brass fire formed in the chamber.

-TL

Sent from my SM-N960U using Tapatalk
 
thats a screw in die for a linkage press, not a inline die for use in a arbor press. No one make inline full length sizing dies for a very good reason. It takes more force than you can generate with a small arbor. If you guys really think you can resize your cases in the rifle then why do the neck sizers bother with full length sizing ever 3 or 4 neck firings ? You would never need to FL size if it is that easy

edit - If someone wants to try just using a neck for multiple firings I would be curious to see at what point it would be impossible to chamber the round. I recommend putting some anti seize or good grease on the bolt lugs to prevent galling before each range session though
 
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tangolima said:
0.003" over saami may be possible to chamber as the chamber is slightly longer. But 0.003" longer than the actual chamber, or -0.003" negative head clearance, is not.
Click to expand...

Again, look at the SAAMI drawings. They are intended to allow the manufacture of cross-compatible guns and ammunition. That means all ammunition within spec should operate in all chambers within spec. The maximum for rimless cartridge cases is most commonly 0.004" over the minimum for their chambers, so this is meant to be compatible. Remember that to gauge a chamber accurately you have to strip your bolt and use a delicate feel because you can close the bolt on an oversized gauge. That is stretching the whole chamber just with the leverage of the bolt handle and the pitch of the bolt lug engagement. Then remind yourself how much more malleable brass is than either gauge or chamber steel.
 
Unclenick said:
Again, look at the SAAMI drawings. They are intended to allow the manufacture of cross-compatible guns and ammunition. That means all ammunition within spec should operate in all chambers within spec. The maximum for rimless cartridge cases is most commonly 0.004" over the minimum for their chambers, so this is meant to be compatible. Remember that to gauge a chamber accurately you have to strip your bolt and use a delicate feel because you can close the bolt on an oversized gauge. That is stretching the whole chamber just with the leverage of the bolt handle and the pitch of the bolt lug engagement. Then remind yourself how much more malleable brass is than either gauge or chamber steel.
Click to expand...
I hear you unclenick. I don't think it has anything to do with saami here. OP believed his brass was 0.003" too long in that particular chamber. I don't think he could close the action, at least not so without feeling anything unusual. One has to use a press to size down a brass by 0.003". With mechanical advantage of a press, it is easily over 1000 lb of force. No way by just casually pushing bolt forward. The only possibility is his brass is not too long.

-TL

Sent from my SM-N960U using Tapatalk
 
A bolt whose closing is strong enough to stretch the whole chamber with an oversized headspace gauge will close on an oversized and much thinner piece of brass with no problem. The OP says himself "it was slightly difficult to close the bolt" on these 0.003" to 0.005" oversize cases. I only mentioned SAAMI to point out this is a normal expectation given their 0.004" compression fit spec is in that same length range. Now, if you have a case so long it keeps the bolt lugs from getting close enough to the receiver lugs to start engaging when the bolt is turned, that's a different story. That would likely prevent closing the bolt. But 0.005" of extra case length isn't great enough to cause that problem in any gun I have.
 
Yesterday, I made a new chamber fireformed replica with brass I had fired that I discovered was .002 longer shoulder than my regular replica.
I checked the brass that I had fired recently and deprimed and found several that were.003 to .005 longer than new replica.
I took one that was almost .005 too long in the shoulder, chambered it and with pretty considerable force, I could close the bolt and then eject it.
It didnt resize it much, I think I measured it to be about a half a thousandth less than before I chambered it.
 
Yes. Without lube, you don't expect a lot of resizing. It's more like the case is a tubular spring and you are compressing it to make it expand outward (barrel distortion) against the chamber walls. You can figure that your fired cases from the chamber have already sprung back about 0.001" from the actual length of the chamber's headspace after firing, so that +0.005" case was already at SAAMI's +0.004" maximum interference fit for your cartridge. That's even better than your OP report these rounds were only slightly difficult to chamber because it confirms SAAMIs thinking that +0.004" is about the upper limit. The SAAMI numbers are critical dimensions (the reason their tolerances are unilateral). A critical dimension is one beyond which a mechanical assembly (in this case the gun and cartridge) cannot be expected to fit together or operate, and you seem to have confirmed that another thousandth or two would not go. I am assuming from this last experiment that when you referred to the slight difficulty closing the bolt in the original post, you were probably chambering the +0.003" cases and not the +0.005".
 
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