.38 Super old chamber inaccuracy

[FieldShunt]

We all know how the old .38 Super chambers were done wrong and how often the older Supers pattern more than group their shots.
I have a '47 Government Model that seems so afflicted... putting in a more modern 9mm barrel and spring results in nice, tight groups that belie the ol' clunker's age and wear.
So when I picked up this '51 Lightweight Commander in .38 Super I expected the worst as well.
In fact, when I finally got it to the range the other day I was packing both lead-bullet 160gr. loads and 125gr Montana Gold jacketed rounds (both with WSF behind them at near-max weights).
My instruction business partner is a sponsored USPSA shooter and was practicing before one of our Intro to Handguns classes getting ready for the Florida Open in a couple of weeks with her Springfield-based Canyon Creek Custom single-stack .40.
I tossed about 15 rounds into one of the USPSA silhouettes with not-great results. I'm not the accuracy bug here and the very heavy trigger (ten-pound-range) and little bitty sights make things worse, but still... not too good.
So I asked TD to take a hand and pop off a magazine full. After a couple of rounds getting acclimated to the gross trigger, a far cry from her competition gun's 2-pounder, she promptly drilled a six-shot group at ten yards with all holes touching.

Guess the chamber's okay.LW Super left.jpg

[kenhwind]

I'm not entirely convinced that the original type of headspacing of the .38 ACP, or Super Auto, contributed to the inaccurracy complaints as much as the legend suggests. The same comments are made about vintage .45s from the same era as well as the GI pistols.

My first .38 Super was a Colts MKIV/Series'70, and was reasonably accurrate, because of some heavy loads I had to replace that barrel with a newer one that headspaced on the case, instead of the rim.

I also had an early 80s Combat Commander .38 Super that headspaced on the rim. I installed some KINGS hardball sights on this pistol and it shot quite well.

The .38 Super wasn't developed for accurracy and isn't known for its accurracy as far as I know. Having a barrel where the case headspaces on the case mouth is most certainly preffered over headspacing on the small rim.

So I guess like most guns some just seem to shoot better than others

[haggis]

The fastest fix for a .38 Super with poor groups due to rim headspacing is to switch to .38 Super Comp. This is a rimless .38 Super that's used a lot in competition. Check the chamber mouth headspacing to be sure the chamber depth is correct before you use them. A small adjustment in extractor tension may also be necessary.

Buck

[FieldShunt]

Buck
It just so happens that I have a couple hundred pieces of Super Comp tucked away so I'm using just the Starline I bought new. I'll give that a try with the GM. Probably am not going to worry about the Commander, though.
Ken, I would have guessed guns as late as yours were mouth-spacers (to coin a term). I must be mistaken about the modernization time.
I just wish I could figure out why the .38 Super is so intriguing... almost addictive.
After all, I'm a .45 guy- who needs a little .38? (Double especially since USPSA killed it with the .40-major rule.)
Oh, yeah, I got the Commander for six hundred bucks. That makes it shoot better right there.
Bill

[kenhwind]

The fastest fix for a .38 Super with poor groups due to rim headspacing is to switch to .38 Super Comp. This is a rimless .38 Super that's used a lot in competition. Check the chamber mouth headspacing to be sure the chamber depth is correct before you use them. A small adjustment in extractor tension may also be necessary.

Buck

The .38 Super chamber that headspaces on the semi-rim of the .38 ACP case will have no support for the rimless .38 Super Comp. There IS NO shoulder in the chamber to headspace on.

But with a Colt barrel made after the early 80s, or a Bar-Sto barrel where the .38 Super chamber was changed so that the case headspaces on the case mouth, then the rim on the .38 ACP /Super case is redundant.

[kenhwind]

Buck
Ken, I would have guessed guns as late as yours were mouth-spacers (to coin a term). I must be mistaken about the modernization time.
I just wish I could figure out why the .38 Super is so intriguing... almost addictive.
After all, I'm a .45 guy- who needs a little .38? (Double especially since USPSA killed it with the .40-major rule.)
Oh, yeah, I got the Commander for six hundred bucks. That makes it shoot better right there.
Bill

No the Series 70 pistols headspaced on the rim, and I guess the Combat Commander was made either just before the change or had a barrel in it that pre-dated this change. It seems to me that Colt changed the way the .38 Super headspaced in their barrels just about the time the Series 80 pistols were introduced. Colt did make the MKIV /Series 70 barrels that headspaced on the case.

"I just wish I could figure out why the .38 Super is so intriguing... almost addictive."
Don't know the answer, but the shooters that like the .38 Super seem to really have an affinity for it. Me I'm one of them.

"Oh, yeah, I got the Commander for six hundred bucks. That makes it shoot better right there." Buying an older Commander, Combat Commander or Government Model in good condition for 600 would seem to make it shoot a bit nicer for sure. Don't hurt too much when you squeeze the trigger.

[Ratzo]

I have a '47 and a '52 Government model Super .38. They both shoot well with their factory barrels. At first I got some primer piercing in the '52 but replacing the extractor fixed that. You cannot use comp brass in a barrel that headspaces on the rim. I also found that when I measured the rim diameter on the Starline brass it was significantly smaller and less consistant than the Winchester brass. So now I pickup Winchester Super .38 brass whenever I can.

[WoodSmith]

You cannot use comp brass in a barrel that headspaces on the rim. I also found that when I measured the rim diameter on the Starline brass it was significantly smaller and less consistant than the Winchester brass. So now I pickup Winchester Super .38 brass whenever I can.

Thanks for the tips. New 38 Super Auto shooter here.

[Ratzo]

Bob, Welcome to the fold. It is a wonderful cartridge that is easy to reload, performs well, and a joy to shoot. You do have to reload this one though. Ammunition is expensive and hard to find.

[Colt75]

It's great ballistics aside, I think a large part of the allure of the .38 Super lies in the fact that it is uniquely Colt. Yeah, other companies have chambered a few guns for the .38 Super but for the most part it has been Colt's baby from the beginning to today. If you are seriously into Colts sooner or later you just have to try the .38 Super. Probably the same can be said for the lovable old .41 Long Colt. As always, JMHO.