Leading near the muzzle question

[brewer12345]

I had tested 35 rem loads from 21 to 26 grains of 4198 and found the highest charge to be most accurate. Everything thing was fine and I even had a perfect lube star on the crown. I decided to try going up to 28 grains in half grain increments. Everything thing was fine until halfway through 27.5 grains of test rounds. Accuracy fell apart and a bullet keyholed. I stopped my test and found leading in the top half of the barrel in the last couple inches. My reading says this is a lube failure. Did the lube just suddenly not cut it as velocity went up? I am just wondering if that is the difference since the powder, brass, bullets etc were identical to the earlier batch that did not lead.

I only gave these boolits one coating of bll. Worth giving them a.second coat and trying again?

[blue32]

I experienced the same problem when working up rifle loads in a 260. I found that Lyman #2 was a minimum for loads exceeding around 1650fps. I've worked with RCBS 80008 up to 2000fps and Saeco green up to ~2200fps without muzzle leading.

Try the extra lube first as the problem is indeed indicative of lube failure but consider hardness if that doesn't work.

[brewer12345]

Oddly enough, I shot the same alloy in 3006 today and ran it up to a charge of 28 grains of 2400 without a hint of leading. Don't have a chronograph but if lyman data is to be believed the lee 150 grainer was doing 2000 fps or better at the top end of my test string.

[Walter Laich]

remember bullet to barrel fit is important

can you post your barrel diameter as well as that of the bullets?

[brewer12345]

Have not slugged the barrel. The boolits are at 3.595, which is as big as my mold casts them. They shot fine with charges up to 27 grains of 4198 (26 and 27 grains were quite accurate, almost 1 hole groups at 50 yards). Half a grain more powder and everything went to pot.

[Catpop]

I’d say lube issue. I just finished a quest finding my 1911 needed .453 to shoot without leading. This determination was found using a lube groove full of bens red. I then tried the same testing but only used bll (bens liquid lube). Leading was again present. Testing is not finished, but I concluded return of leading came from insufficient lube.
Hope this helps.

[35 shooter]

I use 3 thin coats of BLL for rifle shooting up to 2500 fps. with no leading at all.
If you get leading with 3 coats in your rifle it won't be the BLL.
I've never had a speck of lead with either Ben's Red or BLL in the same loads

[brewer12345]

Yeah, I figured lube issue. I think what happened is that the extra half grain was just enough to outstrip the lube that is on the lead and that is when problems started. At lower velocities the lube was enough and I had a perfect lube star on the crown (purty!). I will put another coat on it and try again. If I can get it up to 28 grains of 4198 with good accuracy, I think I will have a solid 125+ yard deer load. For target with this rifle, 26 grains would be the bee's knees.

The 30-06 boolits I pushed pretty fast today had two coats of BLL. I think the extra lube was the difference.

[centershot]

I had tested 35 rem loads from 21 to 26 grains of 4198 and found the highest charge to be most accurate. Everything thing was fine and I even had a perfect lube star on the crown. I decided to try going up to 28 grains in half grain increments. Everything thing was fine until halfway through 27.5 grains of test rounds. Accuracy fell apart and a bullet keyholed. I stopped my test and found leading in the top half of the barrel in the last couple inches. My reading says this is a lube failure. Did the lube just suddenly not cut it as velocity went up? I am just wondering if that is the difference since the powder, brass, bullets etc were identical to the earlier batch that did not lead.

I only gave these boolits one coating of bll. Worth giving them a.second coat and trying again?

Yes and Yes. Maybe even 3 coats.

[scattershot]

Just how much velocity gain do you expect with two grains more powder? Sounds like you have found your load.

[brewer12345]

Just how much velocity gain do you expect with two grains more powder? Sounds like you have found your load.

I am dealing with a carbine length 336 barrel so I am giving up some velocity just due to that. If I can get similar accuracy with a couple extra grains, I will take it. If not, 26 grains it is. In any case, my practice/target load is definitely the 26 grain load.

[Wayne Smith]

I'm guessing, and I emphasize guessing, that it is a combination issue. I'll bet you are at the edge of your boolit's ability to hold the rifling at your accurate load. That plus a possible flaw in your barrel, caused a slight bit of gas cutting and the lube held until the boolit got close to the end of your barrel.

[brewer12345]

Definitely possible. I plan to try another test of the 28 grain load and if it leads again I will know for sure that it was not just a lube failure since I added another generous coat to the remaining boolits.

[Wayne Smith]

Not necessarily, if I am right you are right on the balance point and a little more lube may not do the trick. You haven't told us your alloy, but a touch of hardening may give you a bonus over more lube.

[brewer12345]

Not necessarily, if I am right you are right on the balance point and a little more lube may not do the trick. You haven't told us your alloy, but a touch of hardening may give you a bonus over more lube.

These are cast from AC COWW with a few percent tin added. 12 BHN or so. I did not want to go any harder than that because this is ultimately a hunting boolit, and I may even cast a small run softer than these just for hunting. The reason I suspect a lube failure is that I only put one coat of tumble lube on these originally and I was somewhat sparing. If they still lead with a second coat of lube, I will stop trying to push them quite this hard and declare victory with a 26.5 grain load. That is still doable as a 100 yard cast hunting load with this rifle/cartridge.

[303Guy]

I use 3 thin coats of BLL for rifle shooting up to 2500 fps. with no leading at all.
If you get leading with 3 coats in your rifle it won't be the BLL.
I've never had a speck of lead with either Ben's Red or BLL in the same loads

Would this stand up to a bore that is less than perfectly smooth? My only mint bore rifle is a two-groove - would it work in that?

[brewer12345]

For anyone playing along at home , I tried a twice lubed bullet at 28 grains again and the first thrwe rounds grouped tight, the fourth was an inch away from the others and the fifth was 8 inches left and 6 high. Upon further inspection, 4 and 5 were starting to keyhole. This rifle has.a.clear speed limit, so I will be sticking to about 26 grains of 4198.

[dubber123]

I firelapped my 336 in .35 Rem. The bore looked fine, gun was "as new" only 5 rounds fired when I bought it. After firelapping, I worked up my load with H-4198, and my NOE copy of the RCBS 200, (actual weight is close to 220), will run an honest 2,150 fps with ZERO leading and excellent accuracy. The reason my boolits are so heavy is that my alloy is 50/50 WW-Pure with 2% tin added. MAYBE 9 BHN.

There is only a few reasons a reasonably slow cartridge like the .35 REM can't be run at full throttle with cast. Bore condition and lube quality/quantity are at the top of the list. Keep plugging away.

Oh, and size FAT for Marlins. As FAT as will chamber freely. I think I'm close to .361"

[brewer12345]

I am in

I am unwilling to mess with the bore, so either I shoot cast at 1700 fps or factory jacketed, both very accurate.

Out of curiosity, is yours a ballard or micro groove barrel?

[popper]

IMHO BLL does liquefy under pressure. I tried it with a really soft alloy in 40sw (bad leading/keyholing) 30/30 PB (leading) 308 & 30/30 GCd (no leading, poor accuracy, harder alloy) All rifle had 3x BLL. Again, IMHO, it blows off with high pressure loads and there is no 'reservoir'. Haven't finished my tests in 308 with H.T. alloy. Soft alloy just allows easier gas cutting.