Powder coating gas checked boolits

[gpidaho]

Friends: I'm looking for thoughts, opinions and WAGs here. I've recently been toying with my 30 carbine with PC'd boolits. The moulds I've been using are tha Lee C309-120-R and the C309-113-F, basically the same boolit one RN one FP, both are gas check designs. I'm also using the TL314-90-SWC that is plane base to good effect. The 309=120 drops very large (.313ish) I've been sizing down in steps. Gas check on my Saeco sizer,.311 Lee, .309 Lee then PC and resize to .309 or .310 depending on which gun they will be shot in. This makes for a very good looking PC'd boolit but my concern is that I may be taking the long way around to create no more than a plane base boolit with a firm backside. Having so well crimped on the check and then sealing it on good with PC I may have eliminated the ability of the gas check to open and function as a scraper. This all being moot if it doesn't lead, but still a really Rube Goldberg way to build a plane base. I may need to shield the shank areas and check post PC but that makes it an electrostatic application where ASBBDT seems fine for the 30 carbine. They ain't target rifles. Soooo what do you think, am I making the gas check less effective coating over them. GP

[Yodogsandman]

No, the purpose of a gas check is just to seal off the base to gasses. To prevent gas from cutting the boolit base.

[koehn,jim]

I have found that the powder coat also keeps the check in place if I have to pull a boolit. I don't have to fish the check out of the case.

[MacFan]

I powder coat after adding checks. I find the PC wicks between the aluminum and lead a tiny bit gluing the check on.

[bangerjim]

I ALWAYS GC AFTER PC'ing. They fit tighter! Never a problem. I use both fender washers for ESPC and plain BBDT for 30 cal's of all weights.

Don't overthink it. Just pop 'em on while sizing after PC.

And as said GC's seal, not scrape.

bangerjim

[Beagle333]

It depends on the GC shank for me. Some boolits have small ones and the check fits better after coating. Some are tight anyway and wouldn't go on after, so they get coated. We had a few threads on it and nobody could see any difference in performance, so coat it if you want to.

[gpidaho]

Thanks for the comments guys. My usual routine is as Beagle333s , if the shanks small coat first, if the checks are tight I put them on then coat. One of my favorite uses of powder coat is to use it as a sizing tool. GP

[45r]

My gc's were too tight on my noe 311414 boolits so I tapped them with a 30 cal forster trim pilot.
Works well for seating them in my rcbs luber without getting them crooked.
They scrape on without opening them up.
Shot a 3/4 inch group(best one so far) at 85 yards today using 18.8 grains 1680 and 1 inch with 16.5 IMR4227 from Australia.
Win primers 300Blk.
Want most velocity so haven't tried them without checks.
Accuracy is just as good as wax lubed boolits.

[gpidaho]

45r: Sound like a good idea. I use a home made tool as posted by Ben, just take a long bolt of appropriate size, cut off the head and the threads and taper the end of the shaft. Great little flaring tool. GP

[fcvan]

I used the Lee C309-120 R for 30 carbine for a while and it was ok. I make my own check so that isn't an issue. It turns out Dad bought a SAECO mold for the 30 Carbine but never used it. It is a PB 95 grain round nose. I ASBBDTd them and shot them through my brothers M1 Carbine. I don't think I will use the Lee mold for 30 carbine ever again.

[gpidaho]

fcvan: I have five Saeco moulds and I like them all. For a 95gr boolit in the 30 carbine I'm using the Lee TL314-95-SWC. That boolit really takes a lot of sizing when I PC them but work pretty well anyway. GP

[RobS]

Another thought to the purpose of the GC. As been stated its to stop gas cutting but it is also, and very importantly so, helps to stop potential boolit skid and creates a better launch at the higher RPM's. I seated the GC's first and then powder coated.

[popper]

Have you tried the GC design without GC? About the same pressure as my BO, I'm using coated PB ACWW.

[borg]

I have something interesting from some of my un-checked gas check boolits that were found in the cliche burm yesterday.
Looking under a 10X loupe, I can see dished out gouges on the bottom of the last driving band all the way around,, but none on the rear of the boolit.
The "chips" look smooth like what you see on acetylene cut metal. The gouges look to be about about .040 into the rear of the band.
Wish I could take a micro of it.

[gpidaho]

popper: I've always had better results with the gas checked designs when they wear the check. In only one instance have I had a boolit be as accurate with out it's check (Lee C309-113-F in my 762X39 Encore) I guess I should do more tests in the 30C as it would save a step and as I said, they aren't target rifles anyway. Thanks GP borg: Guess I'm scared to look too close. lol GP

[P Flados]

In 2011 (pre-PC), I was working with a Lee C309-170-F to get a 30 Herrett IHMS ram load for my old 10” contender barrel (1-10” twist intended for lighter bullets, but it had worked ok with 150 jacketed). I was also working with a Lee C309-150-F for chicken/pig loads.

Bullets were cast using a hard alloy. It was mostly wheel weights plus other stuff mixed in. No “extra cost” additives such as tin or babbitt. Bullets tended to run very close to 175 grs and 151 grs for the two molds.

Some home made aluminum checks were cobbled up. I used some left over construction flashing. Check quality was OK but I was not completely satisfied. Loads were tried both with and without checks

After the above, I got a chrony and a 30H 14” barrel (1-14” twist intended to be able to handle heavy bullets for IHMSA). The 14” barrel runs about 100 fps more than the 14”. The 14” chrony data included:

150 gr bullet, 19.1 grs 296, 2030 fps

175 gr bullet, 15.7 grs 296, 1700 fps
175 gr bullet, 16.8 grs 296, 1810 fps
175 gr bullet, 19.2 grs 296, 1910 fps

None of my loads at this time were close to desired accuracy. In fact a lot of the loads were terrible with more than a few showing tumbling bullets. Gas checks were working OK as there was no leading on hot loads.

Long before I got happy, I lost access to the outdoor range I was shooting at.

I did no additional 30H load development until this year. After reading about PC late last year on this forum, it looked like a real solution to my DW 357 max chronic leading problems. The 357 max results with PC encouraged me to reconsider working up some new 30H loads.

Most of my recent shooting has been at a local indoor pistol range that has no benches, no real way to use the chrony and only goes to 20 yds max . I have made one longish (1.5 hrs) drive to an outdoor range and did some chrony testing.

I found that regardless of bullet, powder, lube or twist, I can easily push my 30H bullets to tumble with the no signs of high pressure at the primer.

The 175s start to tumble with anything over 16.8 gr of 296 (1810 fps from the 14”, 1685 fps from the 10”). Best accuracy has all been at less than 16 gr.

Since I was not planning on using the 150 gr bullets for the Rams, I swapped over to my other bulk powder, Promo (Red Dot equivalent) from an 8 lbs jug. When I bought this jug, it was partly for use my 30-06 with cast bullets based on “The Load”, 13 gr of Red Dot (than you Mr. Ed Harris). In my 30H barrels, the 150s start to tumble at something over 1700 fps using 296 / IMR 3031 / IMR 4895. I worked my way up to tumbling with 8.5 grs of Promo and the primers did not look bad. My best accuracy (sub 4 moa) for the 14” barrel has all been 150 gr bullets with between 4 and 7 grs of Promo.

For all of my recent 30H shooting, it has been PC with no check. As long as I am far enough from loss of stability, I think I am able to get the no check bullets to perform reasonably close to what I can get from jacketed.

I think a check can help accuracy, but only in the context of getting a more uniform transition from the side of the bullet to the base. My best results have been with extra care to make sure the lower edges are uniform after coating. I have thought about some kind of custom sizing die arrangement to square the edges up. I might try to make custom ram for my Lee push through.

[bstone5]

I have shot thousands of powder coated bullets in a M1 Carbine, the bullet is a plain base bullet that I install .008 thick gas checks made from aluminum roof flashing.
No lead in barrel or gas system.
The gun stays clean and the gas check makes a good seal.
I use the same gas checks on 32 caliber bullets.
The gas check maker was made on my lathe using the data from Ed Smith published in the gas check section a few years back.

My wife likes the light gun and keeps me busy loading magazines.