First go with .38 Super, Kart barrel, need a little help.

[geargnasher]

I spent a few hours here digging up some excellent information and loaded up some test rounds yesterday, as usual most of what I needed to know I found, and that saved me a few sleeves of primers for sure! I shot them today with pretty good success, but have a little throat leading and need some advice.

First off, the thing slugs .3562-ish, and the experienced guys say just shoot .358" boolits most of the time, so I went with Lee 358-150-R boolits lubed with Felix, sized .358", and seated to headspace on the throat just flush with the barrel hood, this chamber is large but appears to be designed to headspace on the case mouth judging by how far a case will go below flush with no boolit. .358" boolits loaded in Starline competition brass gives me .004" chamber "neck" clearance and .0003" boolit swage on the base band, not enough to matter. I extrapolated a load with Power Pistol, starting with 4.9 grains to be safe. It drives tacks and ejects most of the time, but won't lock the slide back.

20 rounds left a little bit of lumpy lead deposits right at the start of the rifling, and a very light "wash" the rest of the way that patched right out with Ed's. I took a better look at the chamber and throat and noticed there are two steps in the chamber/throat: The big step at the end of the chamber, of course, with a razor-sharp edge transitioning into the throat. Then the throat is cut a long way (looks like about .075-.100" by eyballing it), then ANOTHER sharp, but small step to the "leade" (I guess that's what you'd call it), and the lands are beveled to groove diameter meeting at that step. I'm 100% convinced the leading is due to boolit shaving on one or both of these sharp steps, especially the one from the throat to the rifling.

Now for the question: Has anybody used a Kart barrel on one of these and found the same thing? I've never seen a chamber throat cut with a sharp step between the throat and barrel like this before, it looks like the inside of a telescoping pocket magnet! Chamber, throat, barrel, step, step, step. I would like to try to lap the second step out, but it isn't going to be easy unless I firelap it, and I'd rather not because the barrel is so nicely finished. Any ideas or experience with this?

TIA,

Gear

[MtGun44]

New one on me. Kart barrels have a sterling reputation, so I'd be surprised if it is really
done wrong. OTOH, it may be optimized for jbullets and match accy. so it may have some
features that are not intended to be Pb friendly.

I have shot a lot of .38 Super, but I was making major in IPSC so I was using a really hot
load of W571 under a 147 to 158 gr commercial cast .358 boolit. I once got a batch of
.356 commercial boolits by mistake and 1/2 hit the target sideways at 10 yds and out. Very
bad. That barrel slugged .357.

Bill

[geargnasher]

I don't think there's anything "wrong" with the barrel, it's very nicely made, but I think you're right that it isn't "optimized for cast boolits. It has a muzzle compensator and the tapered OD to fit firmly with the slide when in battery. The guy my FIL bought it from was an IPSC competitor who built it from parts, it's a Frankenstein's Monster but well done. The guy supposedly shot cast in it. The compensator is caked with lead around the muzzle crown, but my FIL ran two boxes of +P Silvertips through it before I got handed the project so I don't know how well it was doing before. FIL said the gun hadn't been cleaned at all and had powder residue in the barrel, but didn't comment on leading, probably didn't think to look that close before running a solvent patch through it and shooting it.

I did get what little copper was in there out and a oil patch/dry patch through it before I shot my cast stuff though it.

I'm going to up the powder charge a tad and run a box of 50 though it to see how bad the lead will accumulate. If it doesn't get much worse and still shoots straight afte 50, I'm probably not going to fret it much. This is a toy for us, not a 300-round-a-weekend competition gun, but if anyone has any ideas to try it would be worth a go to fix.

Gear

[Lee W]

It does seem a little odd. The 45 chamber has that step in it as per SAAMI.

http://www.saami.org/PubResources/CC_Drawings/Pistol/45%20Automatic.pdf

But the 38 Super does not..

http://www.saami.org/PubResources/CC_Drawings/Pistol/38%20Super%20Auto%20+P%20-%2038%20Automatic.pdf


It might be worth asking Kart.

[zomby woof]

I have a .45 that I built for Bullseye shooting years ago. The people who mentored me told the Kart barrels were made for lead. Mine shoots lead very well. we shot Carroll Boolits back then. I always got that leading right after the throat. Now that I'm casting my own, My LEE TL SWC boolits with LLA has the exact same leading profile.

Recently I tried the 45/45/10 with Carnuba with the same LEE boolit. I've fired 100 rounds so far and have no leading.

[KYCaster]

"The guy my FIL bought it from was an IPSC competitor who built it from parts,"



Well, that says it all right there. Most of the IPSC competitors you run into are amateur gunsmiths......even me [smilie=1:......and Bill :drinks:. The big problem is, we're not all GOOD gunsmiths.

It's not unusual for someone building a custom open division gun to buy a 9mm barrel and recut the chamber with whatever reamer he can beg or borrow. If you're on good terms with the original owner, ask him who chambered the barrel and if he can provide the dimensions of the reamer.

Kart has a pretty good reputation for "affordable" barrels and from what I've seen, good customer service. If you can't get the answers you want from the seller, send the barrel to Kart and they'll give you good advice.

Jerry

[geargnasher]

Not sure what the deal is, but they seller isn't the friendliest character. The red dot that was on it (Tasco) wouldn't hold zero and defaulted to two feet low and a foot to the left. I don't think it was damaged in shipping, I think he unloaded it. Springfield frame, Colt slide, Kart barrel is stamped ".38 SUPER", has every extention and gizmo you can think of on it. FIL put a new sight on it before I shot it, much better.

I'm going to check out those SAAMI links, should have done that in the first place, thanks Lee W.!

Gear

[leftiye]

Polish the leade/ freebore? (worked in my .22 Hornet)

[geargnasher]

Last night I tore it down and broke the chamber edge with a 45 degree lap, and did some more measuring for headspace and seating depth. After cleaning it up I drove several dry, unsized WW boolits into the barrel from the chamber end and back out again, none of them shaved at all. The second step (between throat and rifling) is small, so small that I don't think it's as much of the issue as I did before. This is certainly NOT a SAAMI spec chamber, the throat isn't tapered as much, but at least it has one. More shooting will tell.

Gear

[bobthenailer]

I have 2 Kart barrels, 45 acp & 38 super, no problem with leading in either barrel, i shoot cast 99.9% of the time
I also have a 38 super Nowlin barrel with a comp , and it shoots cast with no problems @ .357 or .358 dia. how ever it pays to shoot a gas checked bullet every 25 shots or so.
As far as leading in the comp, in the 38 super ! shoot GC cast bullets or jacketed bullets with a slow burning speed ball powder such as 820 or lil gun and it will blast out the lead from the comp ports after a magazine full , but it depends how far the comp leading is built up as to how many shots that will be required , after that you can mantain the lead build up as nessary.

[MtGun44]

I wonder if the previous owner ran some sort of a reamer into the chamber? There were
9x23 folks out - maybe trying to make a .38 Super barrel shoot 9x23?

I tend to agree with KYcaster - lots of folks break into gunsmithing with their IPSC guns. Some are
nicely done. Some not. My default position on a Franken1911 is to be very suspicious of everything
until proven correctly done.

Bill

[geargnasher]

I stepped out during lunch and shot another 20 through it, this time with 5.4 grains of PP, got about the same amount of leading, but this thing drives tacks!

I put ten in a 1" group with a two-hand hold, weaver stance, at 15 yards, and could see each one hit where the red dot wavered. I do believe they would all have gone in the muzzle end of a .45 ACP if I could do my part. I'm going to shoot it from the bench when I get a chance at 25 yards and see just how well it CAN shoot. BTW I rarely shoot below 1.5" at 15 yards with any 1911 pistol, I just can't hold them that well. Right now I'm going to quit worrying about the lead deposits and focus more on shooting.

Gear

[Grandpas50AE]

Gear, even with the leading in mine that is the kind of accuracy I've gotten with mine as well. Mine is a stainless Kimber, and at 25 yards from a rest, using the 147 gr. Penn TC BB boolits (that now do not lead) I'm getting single ragged holes of about 1 1/4 inches after 30 rounds. It seems to be a very accurate cartridge. I'm also getting very tight groupings with the 140 gr. SWC cast from my Accurate Mold, but still getting a bit of leading with that one. Still have the chatter marks in the barrel, but since the leading doesn't occur with the hard cast Penn boolit, I'm going to try adjusting my seating depth and boolit alloy before trying to lap the barrel.

Love those tight groups, eh?

[Cherokee]

I had a sharp edge to the leade in my Briley match barrel that would give me trouble. I broke it slightly as you did and the problem went away. I still get a light lead wash in the barrel but it cleans right up and doesn't seem to hurt accuracy, which is very good. I don't worry about it.

[KYCaster]

I think that SAMI drawing is the original Colt chamber that head spaced on the semi-rim. Your Kart barrel no doubt has a modern chamber that head spaces on the case mouth like it should.

Jerry

[MtGun44]

All of the newer .38 Supers have been changed over to normal case mouth headspacing
to get accy. The tiny 'semi-rim' was near useless and I think pretty much all of the gun and
barrel makers have realized that they get great accy with case mouth headspacing and
horrible accy with the 'rim' headspacing.

My old Wilson .38 Super is still a really accurate pistol after ~60-70K rounds of HOT loads
thru it. I used to clean it religiously every 4000 rounds or so to keep it reliable. Also, it will
make a chronoed 1400 fps with a 124 Hornady XTP over a Hodgdon book max load of W571.
That would be a pretty serious self defense load if I ever wanted to use that particular pistol
for that application.

Bill

[fecmech]

Layne Simpson in his book The Custom Government Model Pistol asked a question of some of the top "smiths". If they were to build a comp gun that would compete against other comp guns for accuracy and the prize was a million dollars what caliber would they build. They all said .38 Super! It is evidently an inherently accurate cartridge.

[felix]

It's hard to best the natural accuracy of the 35 bore when using today's components. They just all seem to be made for each other. This conclusion is maintained by me seeing the wide range of twists which work (at least passable) for a boolit style and length. ... felix

[geargnasher]

Well, whaddaya know! Went and shot a box through it today with a pinch more powder, and the leading deposits stopped. There are a few little flecs of lead visible in the throat and first 1/2" of the barrel, but they're loose. I checked it every ten shots and it was the same, no significant deposits (other than a little wash in the edge of the lands). I ran a dry patch through it and confirmed that the few loose flecs were lead, although they look like small powder flakes. I guess it's "self cleaning", and it still shoots like a laser, so I'm going to declare load workup is complete.

Oh, one more thing, stupid me. The failure to lock back wasn't a light load issue, it's a dirty mag issue. The follower is gunked up from probably thousands of rounds with no cleaning (previous owner) and although it comes to the top, it doesn't do it FAST enough to push up the slide lock before the slide comes back past the notch. I took it apart and cleaned it good, works fine now, especially with the warmer loads.

Thanks for all the input on the caliber and the Kart barrels,

Gear

[jsizemore]

Instead of adding a pinch more powder to make the leading go away in my Kart barrel, I changed my alloy from coww + 2% tin to 49%soww/49%coww/2% tin. Leading went away. Figure I went from 11/12 to 8/9 BHN. Just gray haze from burnt powder and the occasional fleck of lead. Shoots great.

[geargnasher]

I use a lot of a similar alloy (except only 1% total tin) both air cooled and water quenched, it's a good one. Tough but malleable. I think malleability was the issue here, but I already had several thousand of these cast, sized, and lubed because I shoot them in .38 Special too and I wanted to use them up. I'll keep your advice in mind.

Gear

[crabo]

Gear, I firelapped my 45 acp with the Kart barrel. No leading whatsoever, and it shoots great.