doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Lengthened forcing cones and proof

2-piper the forcing cone may not even the highest area but it is a very close second and the removal of any metal in this area is uncalled for in my opinion. And I have see a few guns that had "forcing cones" elongated to remove deep pitting. How much metal did they loose? Again I question why it was done as much as it being done in the first place. And I would be very unlikely to buy any gun which has had its chambers reamed from 2 1/2 or 2 5/8 to 2 3/4 or worse 3". I want as much metal as I can get four or five inches from my fat nose. You are right it is almost certainly safe if done properly but I contend it is almost as certain to be an unneeded alteration.

The improvement in .410 is most likely due to less barrel scrub of the shot as it enters the bore. If 25% of the shot rubs against the bore in a .410 only 5-7% does in a 12. So you'd expect more improvement in a small bore over a large bore.

I've seen a lot of trap shooters have forcing cones lengthened to 4+", bores over bored and ported. All in the name of progress and looking for that extra edge. Nothing beats ability and practice. It all come down to the "barrel experts" convincing people to get work done so they can make a living too often.

Drew,

Thank you! Very interesting. I wonder if these barrels were individually tested or, more like the automobile industry, the product was tested, but not each unit. I don't recall my 1897 Winchester saying it was proof tested, but it could have. Of course I can see where the early barrels from Belgium were tested, but what about that 870 or Mossberg pump waiting for you at WalMart? I'm not being argumentative, I just want to know what modern manufacturers are doing in our litigious society. They don't seem to be producing barrels that are nearly as thick as almost all SxS. Again, I have not measured these modern mass produced guns, so this is just from casual observation. I have a Ruger Gold Label and while it is quite light the barrels are fairly thick for a least the first 9" or so. I'll have to measure it, I suppose. So, I'm I just imagining this difference between these light repeaters and double guns, or what?

KY Jon;
I agree with all that & I don't lengthen my cones. However I still contend that the average cone job does not constitute a hazard. With the exception of those 4" cones & back bored jobs, which generally aren't done on one of the classic doubles we are talking about here, the juncture of the chamber to cone is still the thinnest point in the entire chamber/cone area. I didn't set up & measure wall thickness but did measure barrel OD on the lightest weight 12ga double I own. This is a LAC/Ithaca H grade with twist barrels & 2 3/4" chamber. "IF" concentric the thickness over the juncture point is .095". Again "IF" the cones were lengthened to 1�" the wall at 4�" would still be .095". If that thickness of wall will hold the pressure at 2 3/4" it will certainly hold it at 4�".
If you loaded both a .410 & A 12 gauge with 3/4 oz of shot the .410 would have about 78% more shot in bore contact. I would not expect lengthening the cones to provide the same benefit to the 12 as to the .410.
The only point I am arguing is the metal in the cone is in about 99.98% of the time not the weakest link in the chain. It would be truly an exceptional case for it to be so.

Agree and thank god for that 2-piper. I've seen too much amature hour gun work to want any extra metal removed on a gun I am shooting unless it is far away from nose, thumbs and eyes. And your point about this is the one area with the max metal there to start with is very valid. But it's still not needed in most cases. What the driving forces to do it? Gunsmiths, writers, or owners thinking it will make a big difference. It's an upgrade that upgrades nothing to me.

Miller, Haven't we seen photographic evidence of that rarity here?

I look at it like this.
Cars used to weigh 6000lbs.
You can reduce material, change materials, until something breaks. Then add back material for a comfort zone.
That's pre-manufacture, and it has worked great for a couple centuries or more.

Can't do that with finished products as easily.

So, scrape away at your barrels at your own risk.

Can you lighten a 55 Corvette? Sure! Would the next guy want you to? Hmm.

Some years ago lengthening forcing cone was a fad in the UK .
The poof house did some tests and came to the conclusion that it made no or no discernible difference to the guns recoil .
The shooting pundits all claimed it improved a guns handling . As gunsmith I did not care one way or the other but was happy to take peoples money off them .
I took up the question of proof with the London proof house as I believed it should render the gun out of proof . They were very non committal at the time giving answers such as "How would you know if it had been done?" . They did not give any definitive answer so as far as I was concerned they did not say that it did so I took it that it did not .
I do not know what current CIP thinking or rules are on this .

Just to baseline, I don't advocate everyone go and lengthen the cones in their guns.

I do have a small number of guns I've modified cones on, all of which are .410, 3" chambered guns, with one exception, a 12 ga BSS which I modified with a 1 1/2" long cone in one barrel and later, a 4" long cone in the other. The 12 ga was modified back in the early 90s during the height of the fad, mainly for my own testing curiosity. My first .410 was modified in an effort fix the butchery done by some moron who ran a common chucking reamer and who knows what else into a 2 1/2" chamber to lengthen it to 3". It was so hacked up inside that the longer cone was the only thing I could come up with to fix it...and it was worth fixing. (See below). I had a reamer maker friend grind a "taper pin reamer" so it would match the chamber dimensions while cutting the new cone at the standard taper pin angle of 1/4" per foot, which gave about a 3" cone in the .410. After that, a fellow Fourtenner saw my patterns and asked me to modify his CSMC 21 .410 and later a M42. I believe I only have modified 2 or three of my .410s and the one below was bought by a friend. So, the discovery of the improvement to the .410 was incidental.

I would not be an advocate of modifying a treasured vintage gun without other rationale than seeking pattern improvement, since it is small potatoes with the exception of the 410.

As observed, we don't have a U.S. Proof House, but are blessed with an abundance of lawyers specializing in Class Action.
It is likely that the barrel proving protocol at Remington was buried in non-disclosure as part of the Garza Settlement.

Interesting that the Loitz index case of 1983 was a 1100 Trap gun bought used, and shot with hand loads.

Loitz vs. Remington Arms
http://www.leagle.com/decision/1990960563NE2d397_1953.xml/LOITZ%20v.%20REMINGTON%20ARMS%20CO.,%20INC.

Garza Class Action
http://www.gunsmoke.com/guns/rem_lawsuit_intro.html

Settlement Announcement
http://www.gunsmoke.com/guns/rem_shotgun_lawsuit.html

I've had no success looking for a descriptions of the barrel testing procedure used by any U.S. maker. Winchester used "loads far exceeding normal power."



The Remington Proof Loads used by Sherman Bell and Tom Armbrust were reported to be 18,560 psi.

Removing metal from the chamber/forcing cone area is absolutely the worst area in a set of shotgun barrels to remove metal......only barrel butcher fools do this. Ruins the barrels in my opinion.

Tailor the ammo to the gun NOT the gun to the ammo.......

Good Luck,

Ed, I disagree with you in that good proofing has allowed lightweight game guns with carefully struck barrels to be used with confidence. We build heavier guns because we shoot heavier loads and there is no proof law and we have lawyers in abundence