NEF single shot headspacing.

W

WayneinMaine

Inactive
Is the following a reasonably safe assumption? A 12 gauge head spaces on the cartridge rim. The headspace is therefore the distance between the breech face and the forward edge of the groove cut into the chamber area for the rim. If a barrel butts tight (no light goes through) against the breech and is properly headspaced, is it properly headspaced in another firearm where the barrel is also tight against the breech face? In other words, can you swap barrels between single shot shotguns so long as the action forces the barrel tight against the breech face? Would it be as safe as the original firearm in terms of headspacing?
 
I believe that NEF/H&R strictly cautions against combining a barrel and receiver that have not been factory fitted.
 
When changing barrels in a fixed breech gun, what you're calling head space is just one factor. Your assumption is correct, but you're not seeing the full picture. How are you going to determine if the breech lock is fully engaged? Typically, it can't be seen. For example: With the replacement barrel you may get a tight fit; but, with the lock engaged only 1/10 of that of the original barrel. It feels tight, but is it safe to shoot? If you're not sure, don't take a chance.
 
derekb said:
I believe that NEF/H&R strictly cautions against combining a barrel and receiver that have not been factory fitted.
Click to expand...

Yes, that's right. NEF/H&R cautions about using your frame as a switch barrel platform (if that's the right word). However, and this is a big HOWEVER, some folks do just exactly that, with great results. There are some caveats, of course and you've got to know which frame youi're working with. The older frames won't work with high powered cartridges and the last time I checked, NEF made two frames.

The internet gurus on switch-barrel Handi topics are over at Graybeard's Outdoors forum. The link to the rifle topics is here, the link to the shotgun topics is here. Go over there and surf around, ask questions, and they'll treat you right.

But again, caution: H&R/NEF cautions against using their frames with any barrel that hasn't been properly fitted to that frame.
 
Oversafe

Sometimes manufacturers recommend things for liability reasons. I am now supposed to wear a helmet while riding a bicycle. In my case I have a very modern strong shotgun receiver and am considering switching between 2 shotgun barrels. Lockup is very good as far as I can tell, I cannot open the spare barrel by force without pushing the release. I'm thinking tie it to a sawhorse and use a string to pull the trigger for a couple test fires? Then check cases for damage? Not that I recommend it or would do it myself except in an extreme emergency, but I knew an old guy who used a hose clamp to keep the action closed on a defective H&R single shot.
 
Lockup is very good as far as I can tell
Click to expand...
How can you tell? Have you used machinist's blue dye, or what?
I cannot open the spare barrel by force without pushing the release.
Click to expand...
I had a hinge gun with a faulty breech block spring. It felt very tight but the gun came open upon firing. Instead of using a hose clamp, I had the spring replaced.
 
I'm not used to discarding anything of use, I have never have been wealthy enough to do that. It seems to me there are 2 issues, headspacing and action lock-up. If a rimmed cartridge (in this case a 12 gauge) headspaces on the rim, then the headspace on the original action has to be between the breech face and the far edge of the rim groove. Therefore if the original barrel fit tight to the original breech face then then headspacing will be fine if the new barrel fits tight to the new breech face. I'm not sure the best way to determine action lock up certainly not while holding it. I would think my motivation would be obvious, if it's a reasonably safe setup then I have a useable 12 gauge barrel, if not then I don't. I don't think safety can be assured or expected by blindly throwing money at a stranger (or gunsmith) in hopes that someone else's assurances are better than my own. There are a finite number of factors involved and I believe a reasonable person with some appreciation of these factors can accomplish a job with a fair degree of safety.
 
Those barrels need to be fitted by a competent smith, or preferably, at the factory - then you will safely be able to interchange things. To do otherwise would be unsafe, and therefore foolish
 
switch

Those two points that were made - about lockup and about not being able to force the gun open - are the critical issues.
The "as far as I can tell part" - covered already. How far can you tell?
The second idea is much related to the first....the fact that one cannot force the action open has little to do with knowing whether or not the locking parts are fully engaged. As strong as you may be, the shotshell is more powerful, generating pressures against those locking surfaces far in excess of what you or I can deliver (8-11K psi).
Pete
 
NEF/H&R doesn't just caution you not to use a barrel that was not factory fitted, I believe they will not sell you a barrel unless you send your gun to the factory to have the barrel fitted.
 
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