K Frame flat on forcing cone

[UNK]

Which generation of the K Frame did they start cutting the flat on forcing cone and which generation did they stop cutting the flat?

[willie]

Which generation of the K Frame did they start cutting the flat on forcing cone and which generation did they stop cutting the flat?

Can you describe the forcing cone in each case?

[UNK]

Can you describe the forcing cone in each case?

They made some changes I think, I dont think it was originally that way, not 100% sure about that, for the k frame and as a result the cylinder wouldnt close unless they relieved the bottom of the forcing cone. As I understand it that makes the cone weak at that point and with 125 gn magnums it would crack split or I have seen a pic online that an entire section of the cone broke out.

Im asking which series of the k frame did they start making that cut and which series did they stop making it.

[jh9]

They made some changes I think, I dont think it was originally that way, not 100% sure about that, for the k frame and as a result the cylinder wouldnt close unless they relieved the bottom of the forcing cone. As I understand it that makes the cone weak at that point and with 125 gn magnums it would crack split or I have seen a pic online that an entire section of the cone broke out.

Im asking which series of the k frame did they start making that cut and which series did they stop making it.

There was always a flat spot on the .38s, dating back to the pre-10s. It was just a tiny, subtle cut compared to later. They removed even more material when they moved the gas ring to the yoke from the cylinder. When they moved the gas ring back to the cylinder later on, they kept the same barrel dimensions with the thinner barrel extension.

More info: https://revolverguy.com/the-smith-we...ory/#more-8202

Dick Baker explained to RevolverGuy that moving the gas ring to the yoke changed the dimensions significantly enough that it was now necessary to remove even more material from the barrel flat than before, to make room for the modified yoke to swing in and out of the frame. This left a significantly-reduced amount of material at the bottom of the barrel extension, weakening what engineers like Baker called the “hoop strength” of the barrel extension.

...

Unlike the previous switch, this modification generated an engineering change number. Collectors know it as engineering change 4 for the Model 19 (19-4) and engineering change 1 for the Model 66 (66-1). Jim Supica, in the Standard Catalog of Smith & Wesson, properly dates this change to 1977 (“1977–Change gas ring from yoke to cylinder”).

...

When the gas ring moved back to the cylinder with the 19-4 / 66-1 engineering change, Smith & Wesson did not return to the less aggressive cut on the barrel flat that pre-dated the yoke-mounted guns. Although it was no longer necessary to make extra room for the yoke-mounted gas ring, they continued to remove an excess of material from the 6 O’Clock position of the barrel extension.

The whole article is worth a read. The answer to the question of when it happened is apparently

somewhere in the middle of the Model 19-3 production, and the latter part of the no-dash Model 66 production

So from somewhere in the middle of that revision they went to the new, weaker cut barrel and never went back.

[UNK]

I am specifically interested in the model 66. As I understand it the current production 66’s do not have any flat cut into the barrel. If that info is correct then If I know at what point that started it would be helpful when looking at used guns.

There was always a flat spot on the .38s, dating back to the pre-10s. It was just a tiny, subtle cut compared to later. They removed even more material when they moved the gas ring to the yoke from the cylinder. When they moved the gas ring back to the cylinder later on, they kept the same barrel dimensions with the thinner barrel extension.

More info: https://revolverguy.com/the-smith-we...ory/#more-8202



The whole article is worth a read. The answer to the question of when it happened is apparently



So from somewhere in the middle of that revision they went to the new, weaker cut barrel and never went back.

[jh9]

I am specifically interested in the model 66. As I understand it the current production 66’s do not have any flat cut into the barrel. If that info is correct then If I know at what point that started it would be helpful when looking at used guns.

Current production 66s are a wildly different animal than the old 66. TBH I think they re-used the model number more for marketing than anything else.

No cut is 66-8 only. The small cut is on small number of no-dash 66s. All other 66s-- most of the no-dash all the way up through the 66-7s-- will have the larger cut.

edit: There are no 66-7s on gunbroker. I think that's where the 2-piece barrel started, so those might have no relief cut... but they didn't make very many of them. So I think the answer is still largely the same: if you want "no cut" your answer is mostly "buy a 66-8 mfg'd from 2014-present."

[UNK]

Perfect. Thanks.

Current production 66s are a wildly different animal than the old 66. TBH I think they re-used the model number more for marketing than anything else.

No cut is 66-8 only. The small cut is on small number of no-dash 66s. All other 66s-- most of the no-dash all the way up through the 66-7s-- will have the larger cut.

edit: There are no 66-7s on gunbroker. I think that's where the 2-piece barrel started, so those might have no relief cut... but they didn't make very many of them. So I think the answer is still largely the same: if you want "no cut" your answer is mostly "buy a 66-8 mfg'd from 2014-present."

[03RN]

I've only seen a few -7s and they did not have a flat on the forcing cone.

[jh9]

I've only seen a few -7s and they did not have a flat on the forcing cone.

Yeah, I assume that's a by-product of the 2-piece barrel.

But the -7s were on the market for less than 2 years so odds of one turning up are probably pretty low.

[jtcarm]

I have a -7. Uncircumcised.