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

I know that this topic has been discussed before, but I cannot find it in my search. Do lengthened forcing cones automatically take a gun out of proof? I'm looking at a London gun with 2 1/2" chambers that has "lengthened forcing cones".
Thanks in advance.

Forcing cone

weather a gun is in proof or not in proof is not an issue here, as we have no proof law or regulation. weather a gun is safe to shoot or is not safe to shoot is an issue here...a gun that has had any metal removed from the barrels should be evaluated by an experienced gunsmith...as there is no universal standard, it up to each smith and shooter to make a determination as to the safely of the gun in relation to the pressure of the ammunition to be fired...

and over the years, i have sold hundreds of guns that have had barrel alterations...have yet to hear of one being unsafe.

Well actually "whether a gun is in proof" actually IS the issue. As Last Dollar wrote in his response in the Forcing cone thread noted by vabirddog, buyers and sellers may have differing opinions on the subject. Whether a gun is safe is an issue, absolutely, but not mine at the moment. I am still unsure whether lengthened forcing cones automatically moves a gun from "in proof" to "out of proof", safety and pressure issues aside.

Proof marks give us chamber size and length and bore diameter at 9 inches from the breech.

Proof marks give no info on the length of forcing cones.

What measurement do you take and compare to what proof mark to determine out of proof forcing cone?

I concur with muchatrucha, it is an issue if it has been altered. Any alteration in Chamber dimensions or forcing cone does take the gun out of proof and should be disclosed as it affects value.

That said, depending on the buyer they may not care if the gun is altered or in fact might prefer it as it may be an alteration they would do if not already done (typically many buyers prefer the chambers lengthened to 2 3/4, but not all)

The effect of any alteration on safety of the gun in terms of blowing up is an individual question that has to be measured and looked at on a gun to gun basis. While Ed maybe correct that he has not gotten complaints, that is not the same as proving the alterations may not have on a couple of cases actually made the gun a question mark for how safe it is. He is correct that in the USA it is up to the individual shooter to determine, but that said most shooters do not possess wall measurement equipment or the experience and judgment that is required for the call so they are in some respects at the mercy of the seller.

I would not hesitate to by an altered gun, given the seller had a return policy as I feel comfortable measuring the gun and determining if I feel safe about shooting it and with how heavy a load.

Blanket statements on safety are not a good way to go, as there is more to the question and shooters must learn and understand the variables and what level of risk they are willing to accept.

If you don't have the knowledge, tools, and experience; then go to a doublegun knowledgeable smith (note not every gunsmith, if not most gunsmiths, understand these issues and has the correct measurement tools)

from a sellers perspective, here in the us of a, whether a gun is in proof or not in proof should not affect its value...what should affect value is the safety of the gun...

if you question the safety of a gun, have it checked by someone with the necessary experience and tools to make a judgement on your behalf...

and never, never, buy a gun without a return policy from the seller.

and it puzzles me that so many sellers on the net do not offer a return policy...

I absolutely care whether or not a gun is in proof. I am concerned about safety and realize I am the final arbiter of safety every time I choose to trip the trigger. However, proof is an institution with laws and regulations and should not be so easily dismissed. There are reasons that the British have proof laws and proof houses. I choose not to buy a gun that is out of proof and that affects the gun's value. Here in the U.S. everyone is free to make their own choices, but to me the value of a gun is negatively influenced by alterations that take it out of proof. Now, whether or not messing with the forcing cones takes a gun out of proof is for others to decide. I'm of the opinion that removing metal from the barrel does invalidate the proof. Others may think differently.

most european countries have proof laws. we do not. wonder why?

and what about china, brazil, japan and turkey? any proof laws in these major firearms manufacturing countries?