DI45 acp Rifle

Hello all!
Looking for suggestions, I recently acquired a Di45 from Macon Armory, and it's a lovely thing, and it shoots great, 1in 5 shot groups at 50yrds is boringly repeatable with 230gr J bullets and 6.0gr of unique.

But with cast, I am getting heavy leading on the bolt tail and gas rings, both with Hi-Tek, and powder coat, the boolit is the MP 452374 nlg mold that drops at 240gs with my alloy of range scrap.
Sized .452 and crimped to .473 at case mouth just to remove the flair, so as to not swage them down.
I have tried a few different powders Unique, AA#7, and Vectan A1, all do the same thing, the barrel is squeaky clean, with no leading, and cleans up with just one wet patch and a few dry ones.
The bolt startes getting sticky from the lead build up on the tail and around the gas rings after about 100 rounds, and after about 200 it gets so bad as to not be able to close all the way.
Gas tube appears to only have carbon in it on cleaning, no lead.

Any suggestions from those that run gas guns with cast is welcome!

Thanks for ya'lls time.

I do not have extensive experience running cast through direct impingement guns, as you request. I do, however, have extensive experience with DI guns in general. And one thing I have seen over the years that fairly well duplicates what you describe is using the wrong gun lube.

Because the DI system causes the gun to puke itself, dumping gas into the action to cycle it, all that residue within the gas can get trapped within the lube coating the surfaces. If it is an inappropriate lube, it will turn into a sludge, and rather than ensure reliable cycling, it will begin to slow and retard the action as the thickness of that sludge increases.

The most common mistake in lube selection for AR15s is WD40. It is on everybody's work bench and works on nearly everything else as a wonder lube, so why not, right? But I've seen WD40 cause an otherwise reliable AR15 gum up and cease functioning in just over 120 rounds, with "clean-burning" surplus ammo.

Now perhaps you are indeed using a "proper" lube, such as Triflow, CLP, Ballistol or other common selections. And if so, then your problem may be elsewhere. But you can also experiment by running the gun "dry", and not using any lubricant at all,...or at least a very minimal amount,...and see if your fouling improves.

I appreciate your response though I don't think it is a rifle lube problem, it's not a problem with jacketed bullets only cast.
The lubes I have tried are Cherry Balmz, which is what Rudy at Macon Armory recommends, as well as Wilson Combat Ultima-Lube II, with the inside of the carrier and bolt left dry the outcome is the same, a heavy deposit of lead on the bolt tail and around the gas rings.
What baffles me, is I would think I would see leading in the barrel if the powder coat or Hi-Tek was getting stripped off at the gas port, but the barrel is always clean.

Well, my next deduction would be that the action of firing the powder behind the bullet in the case is sandblasting the rear of the bullet and atomizing some of that lead into a mini cloud of molten lead vapor. Rather than depositing within the bore, these micro droplets of molten lead are blown into the action and deposit themselves onto where they are most heavily directed, which would indeed be the gas rings and the rear of the bolt, where the gas ceases easy travel and dead ends. The molten lead vapor in the bore, once the bullet clears the muzzle, has easy escape and is evacuated before it can deposit. I once upon a time had the misfortune of doing some pistol drills from the seated position in my car, and would draw and fire over the window sill. My muzzle was only a couple inches above the sill, and afterward noticed a grayish splotch on my light blue paint of the car where my muzzle had been. I assumed it would clean up with some acetone or similar solvent, but no. My muzzleblast had deposited microbeads of molten lead in a cloud on my car's paint, and it was immovable and not going anywhere. My loads were good loads and didn't lead my pistol's bore,...but that molten vapor,...damn that stuff.

Any of the ar15 DI based straight walled pistol cartridge uppers have a similar issue which is caused by lower pressure and increased port size. You need pressure, volume and time to cycle the action. You can usually increase volume if you're low on pressure to get them to work. Your pistol caliber upper has a pretty short gas tube that puts the gas port just ahead of the chamber compared to a standard ar15 in order to maximize the chamber pressure. The gas port in the barrel is also larger than a bottleneck cartridge port to get as much volume down the barrel gas tube as possible. It's the gas port size and location that is causing the issue with plain based lead bullets. Rudy has in the past said that lead bullets void the warranty because of the leading on the bolt tail. You might try harder lead or gas checked bullets. Using harder lead plain base bullets I'm able to get around 500 shots out of DI 9x19's I've made.

Another issue can be if the gas port has a burr on it. On a bottleneck cartridge the burr will quickly be removed by just shooting it, but it takes much longer for lead pistol bullets to wear the burr off and instead the burr acts like a mini cheese grater. If you're getting larger chunks of lead vs a fog or very fine dust like granuals building up, look at the gas port. If there's no burr you might try a diamond bit that fits down the gas port BY HAND to remove the sharp edge on the forward side of the gas port. I drilled the gas ports on mine at a slight angle so the front edge would be more than 90 degrees and less likely to want to shave lead.

The lead is about 12-14 bhn water dropped after powder coating and aged about 2 weeks.

Running a patch down the barrel it feels glassy smooth, and a cotton swab doesn't seem to catch anything on the gas port.
Next time I shoot it, I will take a few pictures of the bolt before cleaning.
Total round count is at about 500 jacketed and about 400 cast if that matters at all.

Your problem is a plain-base bare bullet passing gas port.

Powder-coating "may" reduce it.
Gas check will eliminate it.

I have to wait on gas checks as it seems sages is out of stock on the 45 plane base checks.
Though it seems strange to me that if the bullet was getting some lead scraped off at the port I would see leading in the bore?
Also if if was the bunning gasses from the powder were "vaporizing" the base of the bullet wouldn't I see that with the exposed lead base of a jacketed bullet?
Not being argumentative, just trying to understand it.
Current experiment is a .453 diameter bullet while I wait for checks.
Thanks for the input everyone, any further input or advice is most certainly welcome!

A unprotected plain-base going by the gas port does not produce a 'leading' problem, per se.
Rather, the problem is the base edge being deformed by the effect of very hot/high-pressure gas jet blowing by it, and eroding that edge into the port as it passes.
Clean/uniform edges are a major accuracy factor when exiting the muzzle.
(And note, bolt actions don't have this problem.)

As to exposed-base FMJs... the jacket on the sides of (and rounded under) the
lead core fully protects the base edge from the jet action as it passes the port.
https://upload.wikimedia.org/wikiped...ketBullets.png

I've got a 45acp bolt action so there's obviously no gas system. What mehaey is saying about gas scavenging off the edge of the bullet makes sense. The MP 452-374 is a plain base design, as are most molds intended for 45 acp. Usually you only get the options of plain base or bevel base in this caliber because the 1911 pistol doesn't operate at a high enough psi to require a gas check. There are other actions and platforms chambered for 45 acp, but the overwhelming majority of the firearms in this category are semi-automatic pistols, so the bulk of bullet casting molds are going to be tailored for these firearms.

I did a quick search of MP Molds, Saeco, RCBS, Lee, and NOE, and only NOE offers a .452 bullet mold for gas checks that looks like it might work in 45acp. That mold is their 452-277-RF-BP6. Other gas checked 452 bullets (from all makers) seem to be SWC's that are intended for 45 Colt (and other revolvers) The nose profile on the 452-277-RF-BP6 looks like it might feed in a 45 acp weapon. The bullet casts at 274 grains (according to their diagram), which is a little heavy for the 45acp, but is still within a very usable range. I suggest that you take a look at the bullet at NOE's website, and if you have any questions if it might be a good choice in your platform give them a call and explain what's going on in your carbine.

Try...
https://accuratemolds.com/bullet_det...bullet=45-210G
https://accuratemolds.com/bullet_det...ullet=45-220AG
https://accuratemolds.com/bullet_det...bullet=45-230C
https://accuratemolds.com/bullet_det...ullet=45-230FG
https://accuratemolds.com/bullet_det...ullet=45-230MG
https://accuratemolds.com/bullet_det...ullet=45-230MH

.... many 45 auto gas checked options.
Tom Ellis can/does make just about anything

I tried everything and anything in the DI45

Then I found a solution. Sell it to someone else and get another lever gun. Problem solved.

I couldn’t make it work with any powder/coating. It needs jacketed so it’s not the rifle for me.
Good luck and I hope you come up with a solution.

After quite a bit of experimenting with the .450 in an AR platform I have found that any plain base cast boolit used, regardless of design or hardness will shoot poorly and plate the bolt tail of a direct impingement rifle with lead. As mehavey said, when using plain base cast a small divot gas cut from the base of every projectile as it passes the gas port. I'm assuming that this lead is in a gaseous state which then condenses on the tail of the bolt as the gas tube does not build up lead as you would expect if the lead was in a liquid state coming from the gas port.

GONRA uses:
Ideal 452374 is a nice 230 grain .45 ACP boolit.
Ideal 452484 same thing but uses a GAS CHECK.

Quote:

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Originally Posted by BD

After quite a bit of experimenting with the .450 in an AR platform I have found . . .

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Correctomundo.
:evil: :|

Or you could go with a RDB system that CMMG developed and no more lead on the tail of the bolt

Quote:

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Originally Posted by milsurpcollector1970

Or you could go with a RDB system that CMMG developed and no more lead on the tail of the bolt

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Already have one lol, the problem with the Rdb guns is they arn't very accurate, best I could get is 4in groups at 50 yrds, they all seem to have excessive headspace slop to facilitate function as there are no angles on the barrel extension only on the bolt, also they break cam pins, and in 9mm wear out ejector springs every 1000 rounds.

I am waiting on sage to do another run of plain base checks to get back to this project.

I will have shoot mine for a group to see. At 25 yards they are all touching, that’s the furthest I have shot it with a target. Mostly I shoot steel out to about 75 yds

I run gas checked bullets coated with Alox in a .338 Spectre AR and have no issues with lead build up anywhere. Mostly running sub sonic. I have also run some gas checked Hi-tek coated bullets with no problem.

adding gas checks would be very helpful in your pursuits

Some hypotheses. . .

In my experience, Unique is just too doggone slow a powder for the .45ACP. I've had a lot of incomplete burning and when used with conventional grease-groove lubes on cast bullets, a lot of greasy granules clogging up the works of a 1911.

Bullseye was the official GI powder back in the day, and I've found it to be MUCH cleaner in duty caliber and pocket auto rounds. My thought with regards to a direct impingement gun is that the burn of Bullseye will be complete or at least more complete by the time the bullet gets to the gas port, and this may reduce flame-cutting off the base of the bullet at the intersection of the port.

You might also consider reducing your hardness to about 9-10 BHN. I've been switching to tumble lube mold designs to simplify production, and was getting lead streaks with 45/45/10 lube using alloys in your 12-14 BHN range. Thus far, going softer has helped bore sealing.

Atfsux is also in the right zone with using a correct "lube": What the DI system of the AR actually needs is a combined cleaner/lubricant that keeps fouling inside the bolt carrier dissolved and fluid so that the reciprocating parts can push it out of the way and keep running. I got to witness a good example of this when another agency was renting the bay next to us for their training. They had designated training rifles (5.56) that weren't being deployed in the field, and their "maintenance" practice was to pull the bolt carrier groups out, hose them down with Break Free CLP, and put them back in. A few shots into the gas escape holes in the side of the carrier works wonders. This prevents the "baby diamonds" carbon build up inside the carrier that many can spend hours with specialty scrapers trying to remove. Run the bolt group wet, wet, WET and it pretty much just wipes off with rags and patches. If you're getting lead vapors in addition to carbon, this will at least make it harder for the condensing lead to adhere to anything.

Be very careful cleaning lead off the bolt tail - that is the back side of the gas cylinder, and should be a tight tolerance. Rings are the other end.

As a update on this project, I have acquired a plain base gas check maker, and have made some checks out of some soda cans, and have have had good luck with them seating easily on the boolits already cast and coated, when sized to .452 they are very secure on the base of the bullet. I am hoping to get to get a batch of 100 assembled this coming week for testing, the upper has about 2200 rounds on it currently and has ran great with jacketed bullets, with very little build up on the tail of the bolt, seems like just carbon that wipes off fairly easily.

So far AA#5 has been by far and away the best performing powder with 230gr xtps and 185 haps and 230gr Rmrs.

I do have a lot of Bullseye around, and I will have to give it a go, for 200gr swc out of the comp guns, and bullseye guns, it is a fantastic powder, just haven't tried it in the di gun yet.
My thought processes was the slower powders would provide more volume of gas to run the action, as when I tried Vectan A1 even at the top charge, it was struggling to cycle with a standard carbine buffer, it did cycle with a gutted buffer.

If jacketed bullets are ok then try gas checked lead bullets. I have Olympic Arms blowback and CMMG rotary bolt guns and other than sooty brass have no issues. All are 45acp and use CNC Enterprises dedicated greasegun mag lowers. I corresponded with Rudy when I was building my first couple pcc’s but never bough his system.