doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Chamber sleeving

What happens when you chamber sleeve a 16 to a 20 ga?
1. How will this affect the pattern?
2. I'm assuming this means the whole barrel is considered
backbored?

I think TW may have done this and can provide some performance information.

But, my question is: Why? If the chambers are damaged, why not sleeve to the orig gauge?

I think you may be confusing "sleeving" with "lining". When I think of sleeving I think of barrels cut just past the chambers, with a portion reduced in diameter and slipped into a new set. New barrels on old chambers. Lining, as with Briley full-length tubes, does reduce the gauge and balance but enables you to shoot a 20 gauge in an old 12 that may be unsafe for 12 gauge shells. Teague liners are another matter entirely.

I think it has been proven that chamber liners that reduce chamber one gauge step work OK with plastic wads. The issue is that the wad must obtrude to fit the bore. If the wad performs appropriately, patterns would be unaffected. Compared to a normal/spec barrel, this would be a back bored barrel.

"What happens when you chamber sleeve a 16 to a 20 ga? "

"chamber sleeve" is a good term. By analogy, Brownells sells "choke sleeves", not "choke liners" for the muzzle end.

"1. How will this affect the pattern?"

My guess is....not in any statiscally significant way. And it would be extremely difficult to design a really definitive experiment. It would be relatively easy to do if you were just enlarging the bore because you would test the exact same shell under controlled conditions before and after the bore enlargement. But in this case you'd be patterning a 16ga shell first and a 20ga shell later, which introduces a lot of other variables.

"2. I'm assuming this means the whole barrel is considered
backbored?"

Actually, to be more precise, it's "overbored." Since we have two terms, seems they ought to mean different things. Some accept the distinction that "overbored" is a larger than standard bore from the beginning while "backbored" implies a post-manufacturing enlargement.

Try it with a Brownells " little skeeter" chamber insert. You can get the answer for your gun for less than 30 dollars.
bill

http://www.gaugemate.com/

I've used 16 to 20 Little Skeeters, they "shoot" very well but... The 20 ga. fired hulls will stick in the Little Skeeters.

Gauge Mates are a superior design and competitively priced.

Performance wise the 20 ga. ammunition is equal to the comparable 16 gauge load in every way. If chamber inserts serve your purpose definitely go for the Gauge Mate product.

Craig

I have a ten ga with a chamber sleeve to 12 and it patterns great
and works well. I also have a gauge mate from a 10 to a 12 and it works well also. Good idea!

I currently have a couple of long barreled J P Sauer guns in 16 gauge, one 29 1/2" and the other 30". I am seriously considering chamber sleeving (yes, that's a correct terminolgy) probably one of these down to 20 gauge simply because I can't seem to find an older pre war 20 gauge gun with similar long barrels. The weight of both these guns is such that they would make excellent long barreled "overbored" 20 gauge bird guns, which is what I am after. I have a number of guns from which to choose an upland gun, and I have grown to much prefer pre war German guns for a number of reasons. Not many 20 gauge specimens around, it seems. If your goal is something similar to mine, or whatever your goal might be, chamber sleeving a 16 down to 20 is a perfectly feasible thing to do. If it should happen to be a fairly hefty gun, it might not make up into a particularly sweet swinging 20 gauge, but in my case, I believe both my guns will.

Briley is, or was doing chamber sleeving for a while. It was written up in one or more of the hook 'n' bullet rags. I never completely understood for what it was a cure. You'd have no forcing cones, or maybe even a negative one. How thrilling would THAT BE! Unless the chamber was dangerously thin at the forward end it seems like low pressure shells would be a much more practical answer.