This question may have been answered somewhere before. Has anyone slugged a BSR (British Service Revolver) bore and compared it to a .38 special Victory slug? I know that the .38 S&W barrel should be slightly larger in diameter, but is it?
.38 S&W bore diameter
- Thread starter Muley Gil
- Start date
S&WIowegan
US Veteran
Good question
We know a number of British Victorys were sold back to the USA and cylinders were modified to accept 38 Special cartridges. I've never heard anything about barrel changes.
I have a 38-200 in my safe(somewhere). If I can find it I'll slug the barrel.
We know a number of British Victorys were sold back to the USA and cylinders were modified to accept 38 Special cartridges. I've never heard anything about barrel changes.
I have a 38-200 in my safe(somewhere). If I can find it I'll slug the barrel.
I will be very interested in seeing your results. First, because accurately measuring a slug from a bore with an odd number of lands and grooves can be tricky. Secondly because from a production standpoint there would have been no logical reason to have one production line set up for 38 S&W K frame barrels and another for 38 Special barrels. So I think the bores are the same.
Absalom
SWCA Member, Absent Comrade
The nominal difference is .357 to .361.
It would indeed be interesting to see a comparison of actual difference. Just as it would be enlightening to compare several barrels of each and see the degree of variance within each.
The difference in nominal neck diameter is actually greater than in bullet diameter: .379 to .3855. Yet there are plenty of cases of (unaltered) .38 Special chambered guns fully seating .38 S&W cartridges. It might be interesting to find out whether similar tolerance margins prevailed in barrel production.
It would indeed be interesting to see a comparison of actual difference. Just as it would be enlightening to compare several barrels of each and see the degree of variance within each.
The difference in nominal neck diameter is actually greater than in bullet diameter: .379 to .3855. Yet there are plenty of cases of (unaltered) .38 Special chambered guns fully seating .38 S&W cartridges. It might be interesting to find out whether similar tolerance margins prevailed in barrel production.
Do you really think that S&W was actually that lax on tolerances?? They probably produced tens of thousands of cylinders that were all made on the exact same set of machinery. I have read, heard stories, but never ran across anyone who documented the fact that they had an unaltered gun. I guess I do not think would be easy to detect unless a conversion was done in someone's basement with a hand drill.
All I know is that shooting 38 Special in an altered 38 S&W can result in split cases, and relatively poor accuracy. I used to own a couple of altered 38 S&W M&Ps and both exhibited those characteristics.
Walnutred makes a good point, but I think we're going to find .361" is a good number-----at least that's the bullet diameter. Perhaps not coincidentally, it's also the bullet diameter for the .38-44 S&W---as in the cartridge Ira Paine designed---used in the New Model #3 Target-----with the cartridge case the same length as the cylinder (bullet seated entirely within---as in zero throat---as in super accurate and (supposedly) set records that (supposedly) still stand today---never mind I've never been able to find them---and never mind I haven't looked all that hard.
Ralph Tremaine
Ralph Tremaine
Absalom
SWCA Member, Absent Comrade
Yes, absolutely.
The workforce at S&W had been ballooned several-fold over the span of just a year or so in 1941/42, as monthly production expanded dramatically, and I doubt they were able to pull large numbers of experienced machinists from the unemployment line. Refer to Kevin’s post #18 in the thread about the AR Victory article regarding the lack of blueprints and 30% failure rates per Ordnance report.
All that nostalgic twaddle about “old time craftsmanship“ goes out the window when it comes to wartime production, and that’s what we’re talking about here.
OP
"...I doubt they were able to pull large numbers of experienced machinists from the unemployment line."
A whole lot of those folks were in the service.
Common knowledge is that the .38 S&W is larger in diameter and wouldn't fit in a .38 special chamber. However, when I was studying criminal justice in the mid 1970s, one instructor brought his NYPD Model 10 to class, together with several .38 S&W cartridges. A combination of a generous chamber and minimum exterior diameter allowed the S&W round to go into the special chambers.
A whole lot of those folks were in the service.
Common knowledge is that the .38 S&W is larger in diameter and wouldn't fit in a .38 special chamber. However, when I was studying criminal justice in the mid 1970s, one instructor brought his NYPD Model 10 to class, together with several .38 S&W cartridges. A combination of a generous chamber and minimum exterior diameter allowed the S&W round to go into the special chambers.
I can understand that WWII era would have called for quantity over quality. Didn't the government take over production during that war? I only have one M&P that new and but it will not accept a 38 S&W round. I also grabbed the most worn M&P I have, and it is from WWI era with no finish and not a sharp edge to be found. Even with a worn bore and chambers, I could not get a 38 S&W go fully chamber. Went in about two-thirds of the way, but I could not push it further. I must have pushed too hard because I had to get our a wood dowel rod and pound it back out of the chamber.
I once owned a modified Victory, 3" barrel with adjustable sights. The cylinder was not serial numbered to the frame so while the barrel was marked 38 Special I wasn't sure how the cylinder was chambered. 6, 38 Special rounds fit in the cylinder. Wondering if it was a reamed BSR cylinder I tried 38 S&W cartridges. Three chambers would accept 38 S&W and three would not.
Pre-war Colt 38 Special barrels tend to run in the .355 range. So the difference between a S&W made 38 SP barrel and the assumed bore of a 38 S&W caliber barrel is not that much different than the difference in bore between a Colt 38 SP barrel and a S&W made 38 SP barrel of the same era.
Anyone who has spent much time working up loads for old European military bolt action rifles will tell you variation in bore diameter is the norm, especially in wartime production.
Pre-war Colt 38 Special barrels tend to run in the .355 range. So the difference between a S&W made 38 SP barrel and the assumed bore of a 38 S&W caliber barrel is not that much different than the difference in bore between a Colt 38 SP barrel and a S&W made 38 SP barrel of the same era.
Anyone who has spent much time working up loads for old European military bolt action rifles will tell you variation in bore diameter is the norm, especially in wartime production.
Last edited:
GypsmJim
Member
- Joined
- Oct 16, 2009
- Messages
- 3,943
- Reaction score
- 6,826
Specs for a 38 S&W show a larger bullet diameter vs. a 38 S&W Special. However, some of my manuals show loading data using 0.358 cast bullets for both of them.
I have an "altered" 38-200 Victory with the chambers reamed to allow the larger special case. I have shot both cartridges in the gun, both reloaded with 0.358 SWC bullets. I don't see much difference in accuracy.
Naturally, the S&W's fit tighter in the chambers, but to say the Special cases split means that the operator didn't mind his p and q's.
My "Victory Specials" come from once-fired 38 Special cases. I simply neck size and then fire form to the 38-200 chamber. Subsequent loadings are once again not fully resized. Never had a split case yet.
I have an "altered" 38-200 Victory with the chambers reamed to allow the larger special case. I have shot both cartridges in the gun, both reloaded with 0.358 SWC bullets. I don't see much difference in accuracy.
Naturally, the S&W's fit tighter in the chambers, but to say the Special cases split means that the operator didn't mind his p and q's.
My "Victory Specials" come from once-fired 38 Special cases. I simply neck size and then fire form to the 38-200 chamber. Subsequent loadings are once again not fully resized. Never had a split case yet.
Absalom
SWCA Member, Absent Comrade
No, that was WW I, and only on the management, not the production side of things.
But I checked the Ordnance report from Dec. 1942 that Roy published a few years ago to refresh my memory on numbers: from 300 employees in 1940 the factory grew to 1500 by the end of 1942. This time period coincides with the shift to ultimately exclusive production of the two M&P variants.
So simplifying somewhat, they were training four new people per experienced worker at the same time that they were under pressure to accelerate and increase the volume of production.
It‘s actually impressive that 70% of guns did pass final inspection on the first try
Recognize S&W had been boring 38 S&W barrels for almost 75 years with its unique barrel dimensions and as used in the 38/200 Victory models. S&Ws chambered in 38 S&W all have the original production tolerance groove diameter of .3595" -.3612" and Bore of .354" per Roy.
The new .38 spl arrived in 1899 with the first K frames in that caliber with its own unique bore dimensions.
So .357"-.358" bullets work quite well I'm told with no demonstrable accuracy difference using standard loaded .38 Spl ammo. With hotter loads the possibility exists that .357-.358 bullets may strip the rifling depending on the hardness.
The new .38 spl arrived in 1899 with the first K frames in that caliber with its own unique bore dimensions.
So .357"-.358" bullets work quite well I'm told with no demonstrable accuracy difference using standard loaded .38 Spl ammo. With hotter loads the possibility exists that .357-.358 bullets may strip the rifling depending on the hardness.
Last edited:
Yup, years ago, I loaded soft lead for the old guns and got keyholes with the rechambered British guns when using 357 bullets. That is why I no longer own them.
mod57
Member
Hondo,
So help me understand as I am clearly missing something. The groove diameter of the .38 S&W is .3595-.3612 with a bore diameter of .354.
What is the bore and groove diameter of the .38 spl.?. Are we sure that the BSR bore/groove diameter is that of the .38 S&W or did they just use the the .38 spl measurements but roll marked for the .38 S&W?
"Recognize S&W had been boring 38 S&W barrels for almost 75 years with its unique barrel dimensions AND AS USED in the 38/200 Victory models."
Why ever, after 75 years, would S&W change the 38/200 barrels from the correct .3595"-.3612" groove and .354" bore diameter to the incorrect .357" dimension of the 38 Spl??? Yes, of course 38/200s most certainly have the correct 38 S&W barrel dimensions.
J. R. WEEMS
Member
38S&W
With NO disrespect to any of the above. the bullets I use are .360, resized from .361. Two Victory's, two Ca. 1921 I frames and a couple Hammerless, all tested, and shot very well with my loads. Just works for me. Others may have a different experience there is no claim here to be any kind of expert, only that I approached these loadings with the utmost of caution.
With NO disrespect to any of the above. the bullets I use are .360, resized from .361. Two Victory's, two Ca. 1921 I frames and a couple Hammerless, all tested, and shot very well with my loads. Just works for me. Others may have a different experience there is no claim here to be any kind of expert, only that I approached these loadings with the utmost of caution.
Your bullets are perfect for a 38 S&W barrel and do not think any of us would dispute that. A .001" difference will still totally engage the rifling, both lands and grooves.
The potential problem lies in the fact that a .357" bullet is .004" smaller than the 38 S&W groove diameter. Assuming that one had a barrel with a .361" groove and .005" depth grooves is shot with a .357" bullet. There would be only a .002" contact with the groove, allowing for the bullet to blow past the rifling with no or only partial engagement. Of course, pressure, lead hardness, actual bore dimensions all vary and the right combination will result in acceptable accuracy.
It is understood that there is a tolerance in barrel and cylinder manufacture, but how much barrels and cylinders varied may not have been documented. I assume that there were acceptable and unacceptable limits in the inspection stages at the factory, but if the factory did not do this, certainly the governments who bought these guns during wartime did have acceptable tolerances.
mod57
Member
Weii I re-read your earlier post, which is something I clearly should have done before I allowed my fingers anywhere near a keyboard. You lost me when you alluded to .357 bullets possibly stripping the rifling. I failed to make the distinction that you were discussing the modified BSR. My apologies to you sir.
