Leading with MBC IDP#4

[918v]

Here is a Storm Lake 10mm chamber:



Why would a Storm Lake 45 ACP chamber be any different?

 

[918v]

Here is a Storm Lake 9mm chamber. Note it has a freebore as well:

 

[Walkalong]

Here is my [strike]Storm Lake[/strike] Bar Sto 9MM barrel. It too has freebore. It also has a defect in the way of a machine mark all the way around near the end of the chamber. Shoots great thought. You see the defect, the chamber end, the freebore, the leade, and the rifling. Wish I could have gotten a better pic.

 

[918v]

Does an empty sized case fall way below flush with the barrel hood?

 

[918v]

Here's a .357 Sig chamber. It clearly has a freebore

 

[Walkalong]

Talk about going the extra mile for a pic.

 

[Walkalong]

Well don't I feel silly. The Storm Lake barrel is in my Colt .38 Super. The barrel I put in my S&W is a Bar Sto. *sigh*

Anyway, here is a pic of a case in the chamber. It is a little above flush.

 

[918v]

I was wondering if that machining defect was actually an overcut chamber.

 

[Walkalong]

Doesn't seem to be. Just a bad spot. Maybe that is why I got it reasonable. Maybe the first fellow noticed it before he fit it to his gun. Not gonna lose sleep over it though.

Here is the Storm Lake 9MM barrel.

 

[918v]

Thats a pretty short freenore. Betcha you gotta load those XTPs to 1.080" or so.

 

[Walkalong]

I am loading 115 RN at 1.1030 to 1.135 OAL, 124 RN at 1.140 to 1.145 OAL. I am loading the X-Treme 124 Gr HP at 1.060 +/- OAL. It really likes those.

 

[918v]

OK,

I emailed Storm Lake last night regarding their 45 ACP freebore and got a response this morning:

"That dimension is .452-.453."

So, It looks like the bore, the freebore, and the bullet are a match. I therefore conclude the OP's OAL must be the culprit.

OP, make a dummy round and figure out your max OAL for that bullet. Keep in mind it does not have to pass the plunk test, just that it is able to chamber under finger pressure. Settle on an OAL that is right at the rifling. Then repeat your test. I think your leading problems will be gone.

 

[Walkalong]

Here is a thread with pics on just how easy it is to find the max OAL for that bullet and that barrel.

http://www.thehighroad.org/showthread.php?t=506678

 

[dickttx]

I load the MBC Cowboy #4, which is the same bullet but at 12 BH instead of 18.
I load it with 5gn of HP38 and 1.195 OAL. NO LEADING. Very accurate.

 

[blue32]

Sorry about my absence. Thanks 918, I'll try that. In the meantime, switching to 5.5 gr. of Unique solved the problem. I will adjust my OAL when switching back to BE.

 

[ArchAngelCD]

Sorry about my absence. Thanks 918, I'll try that. In the meantime, switching to 5.5 gr. of Unique solved the problem. I will adjust my OAL when switching back to BE.

Why would you switch back to BE if Unique is working well for you?
I still think BE is too fast a powder for this application and apparently do does your pistol.

 

[918v]

Bullseye is too fast for lead bullets in the 45 ACP???

Or is it something else?

 

[LiveLife]

Glock 30 with Storm Lake barrel, 3.78", with a bore diameter of .451 ... Leading starts as a ring just before lands and grooves and continues down barrel maybe a quarter of an inch after only a few rounds. I've tried a range of 4.6 gr. to 5.6 gr. of Bullseye with no change in leading. Would a change in COAL help and how much? I'm really stumped on this one ... I get the same leading with a standard glock barrel too.

... switching to 5.5 gr. of Unique solved the problem. I will adjust my OAL when switching back to BE.

Why would you switch back to BE if Unique is working well for you?
I still think BE is too fast a powder for this application and apparently [so] does your pistol.

Bullseye is too fast for lead bullets in the 45 ACP???

Or is it something else?

918v, I think ArchAngleCD may have made that comment because OP experienced leading issues with Bullseye powder but not with Unique.

Missouri Bullet's IDP#4-XD (200 gr. RNFP) over 5 gr. of Bullseye. COAL - 1.92"

I feel for OP as my Glock 30 did not feed SWC bullets and had to use RN profile bullets (Perhaps OP could consider trying 225 gr TC "FlatHead" bullet to see if the feeding/leading is better). I could send the OP some bullets to try (PM sent).




IMHO, as illustrated by 918v/Walkalong with the Storm Lake barrels having freebore right before leade, longer OAL should decrease this leading issue at the chamber end. I think the OP is experiencing gas leakage/gas cutting around the bullet with the Storm Lake/Glock barrels as the bullet jumps through freebore/leade to the start of rifling as I experienced similar fouling deposit pattern with other Glock barrels as well. With my Sig 1911/M&P/Lone Wolf barrels without the "freebore" before the leade, this fouling/leading deposit at the chamber end is less.

I have used Bullseye for 45ACP and 9mm jacketed/lead loads and liked it for great accuracy with a definitive thumping recoil. For me, recoil impulse from W231/HP-38 was less snappy and accuracy was close to 95%+ of Bullseye loads. Since I shot USPSA action pistol with fast double-taps to 25 yards and not slow-fire bullseye matches to 25-50 yards, pinpoint accuracy was not a factor and I made the switch for my match powder.

Other match shooters suggested Titegroup for more economical loadings with comparable accuracy to Bullseye but since I was looking to switch from 45ACP/9mm to 40S&W (to better meet major/minor USPSA power factor requirements) and because I observed several KaBooms along with bulged cases, I decided on lower pressure W231 target loads using Montana Gold jacketed bullets. I tried Bullseye for 40S&W but found the recoil more snappy than W231/HP-38 loads.

BTW, for OP's 45ACP Missouri 18 BHN 200 gr RNFP bullet (IDP #4-XD), I use 1.195" OAL with 5.0-5.5 gr W231/HP-38 and these loads produce accuracy on par with 200 gr SWC bullet loads (12 BHN Bullseye #1/18 BHN IDP #1). I also like 4.0 gr of Promo/Red Dot loads with same bullets that produce accurate and mild/light recoiling target loads.

YMMV depending on pistol/barrel used.

 

[918v]

BDS:

You should assemble all your THR posts into a book, then let me edit it

 

[blue32]

The Unique solved the problem - per se. The 5.5 grains of it doesn't generate the recoil I was used to with BE... the Unique was quite a bit less. I'd like to make it work with BE because that's the load which simulated felt recoil of my defensive rounds. If I can't make BE work, then yeah, I'll work up some with Unique. I shoot almost exclusively from a concealed draw standpoint at 7-10 yards so I don't need stellar accuracy, but I do need it to feel like my carry rounds. I'll play around with OAL like 918 suggested and report back.

 

[ArchAngelCD]

I'd like to make it work with BE because that's the load which simulated felt recoil of my defensive rounds.

Well that sounds like a good reason to stick with BE even though Unique solved the leading problem.

918v, I think ArchAngleCD may have made that comment because OP experienced leading issues with Bullseye powder but not with Unique.

Yes, that was the exact reason...

 

[blue32]

I tried an OAL of 1.198 and went up and down from there. The closer I got to 1.2, the more the leading worked its way from the free bore to the lands. Guess its Unique from here unless one of you can propose anything I might be missing.

I did have a plus from all of this - I learned about the importance of free bore. Thanks

 

[918v]

What was the maximum OAL that you tried? Was that a length where the bullet was touching the rifling?