gas check thoughts

[Lloyd Smale]

as per my other post ive been having problems with keeping checks on my 300 bo bullets at top end loads. I usually install checks size to crimp them tumble them in pc and back then size again. I got thinking that because im dealing with two different metals if its possible when heated up the check looses some of its grip and doesn't shrink back as much as the lead does. Someone suggest my alloy (about 22bhn) is to hard and maybe the gas checks cant bite into it. Like I said the check seem to go on nice and snug and there sure not loose on the shanks. Any thoughts? I had to make a hard decision yesterday and melted down about a 1000 of them I had done that were giving me this problem that I hadn't loaded yet and have about a 1000 rounds of ammo im probably going to pull down because they have those bullets in them. . As you know that's a lot of work and gas check down the drain but it does me no good to have bullets that don't work right. I guess I could shoot them up and just clean the barrel every day but those 1000 rounds were put away for just in case and I want them right. Even all nicely stacked in an ammo can on loading strips.

[mattw]

LLoyd, are all of them coming off? I ask because I have not had that problem with my 300BO. I am running a 152 grain SP cast from 94/3/3 and checked with either Hornady coppers or Sages aluminums. With PC, that bullet does seem awfully hard, I could see that shrinkage could cause an issue, but I would think that would be resolved with a second pass thru the sizer. What are you expanding with? I am using an M die and it does stress relieve the entire length of the neck, could it be that the base of the neck is to small and is stripping off the checks on the way out?

[Dragonheart]

I do think you alloy is much harder than needed for a PC bullet, but I am surprised the PC has not bonded the check in place, especially if it cannot be pulled off after it is crimped. Are you sure your coating is properly cured?
Sounds like it is too late now, but I would have considered doing a second coat to see if that made a difference. I agree you do need to find the problem before going forward again, no point in doing the exact same thing over again and expecting a different result.

[Lloyd Smale]

some new testing today. I started pulling bullets on loaded rounds using a pair of side cuts and a single stage press. About one in every 15 or 20 leave the check in the neck of the case when the bullet is pulled. Ive seen that before with other round but not quite as high of a percent. Then I got to the batch that I had figured the pc might be the problem and put a second coat on them and sized them again. Every one of those rounds had the gas check stuck in the neck. there was a 110 of them. So something has to be going on with heating the lead and copper and letting them cool. The copper checks have to be loosing some grip in the process. I was hoping for actually it happening less often due to two coats of pc holding the check on but I would have to say in reality pc does little to help hold a check on. I melted took the first 20 lbs of the alloy I was using that went about 22 bhn and mixed it 5050 with ww which should give me 18 bhn. Out of checks though so I ordered 2k and even to take the paint going bad out of the equation ordered some more of the mustard yellow that smoke says takes high velocity the best. Ive been using an m die to flare. I ordered a lee flaring die too but it only does the mouth and im thinking that the m die to flare kind of opens the neck up to a consistant size and the lee would be tighter yet so I think ill keep with the M die. But then a tight neck sure shouldn't be stripping checks off that are crimped on. by the way I ordered gator checks this time instead of sages copper checks. I still have to think that the heat has some play in this. If not after running an m die in the neck why would I have more resistance pulling some bullets then I do others. I also decided to do the next batch seating checks in my star sizer to take that out of the equation too. I will run them bare through my star 309 to seat the checks and run them through the lee 309 after pc'ing. Only problem is with this **** is I don't have the time or patients to try each change separately so it going to be throwing everything at it so I might not ever know what the real problem is or if its a combination of a couple things. PULLING MY HAIR OUT GUYS. Oh well a couple years ago before pc I probably wouldn't have attempted to run a gas operated ar a 2000 fps with cast bullets.

[Dragonheart]

You didn't mention checking that you coating has properly cured. I know that back to basics time and temp, but something is amiss. My coating bonds the check on like it is part of the bullet. I realize a properly seated check should stay on, but the PC makes for sure.
Good luck, but as you say you may never find the problem I just hope you find the cure.

[popper]

I assume the GC comes off after the muzzle. Most of my GC are still in the neck when I pull 30/30 or 308. The GC is PCd. I use the LEE die set for BO, no problem but only recently fired GC boolits from it - they did fine. I can't tell the difference between annealed or not GC but the cooking process does sort of anneal them. I mostly use the hornady GCs. I run a WD alloy of 4% Sb with Cu - NO tin (it tends to sweat out at lower temp). I load so that the edge of the GC is IN the neck- you didn't say what mould/load you are using.

[Lloyd Smale]

using smokes powder and cook them for 20-30 minutes at 430.

You didn't mention checking that you coating has properly cured. I know that back to basics time and temp, but something is amiss. My coating bonds the check on like it is part of the bullet. I realize a properly seated check should stay on, but the PC makes for sure.
Good luck, but as you say you may never find the problem I just hope you find the cure.

[Lloyd Smale]

its a 130 rcbs pointed spitzer. Gas check is in the neck at the dept im seating them. I don't know if there coming off in the barrel or after they leave. My guess is it has to be after because the gas pressure should keep them on in the barrel. I guess I cant see that a gas check is one very tight or actually bonded by pc if it comes off in the neck just with neck tension and not even a crimp. Ive had them stay in the case a few times in the past with other calibers but ive allways been able to trace it to a base that isn't perfectly filled out or a non crimped gas check like the old lymans. Id have to think that if your gas checks on a pc bullet are being pulled off in the neck the ONLY thing that's probably keeping them on the bullet is the pc paint. Ive put conventional lubed gas check bullets through the shoulder of a buffalo and found recovered bullets that still had the gas checks on them. Did a ton of penetration testing too and don't recall (again other then lyman checks) a gas check that came off. If a check will hold up to that it sure should hold up to being slowly pulled out of the neck of a case. One bright spot in all of this is the gun is moa for 5 shots at a 100 yards with 4 out of 6 bullets I tested with the same charge of 19 grains of 297 and a cci primer. For all practical purposes I don't even have to do anymore load development with jacketed.

I assume the GC comes off after the muzzle. Most of my GC are still in the neck when I pull 30/30 or 308. The GC is PCd. I use the LEE die set for BO, no problem but only recently fired GC boolits from it - they did fine. I can't tell the difference between annealed or not GC but the cooking process does sort of anneal them. I mostly use the hornady GCs. I run a WD alloy of 4% Sb with Cu - NO tin (it tends to sweat out at lower temp). I load so that the edge of the GC is IN the neck- you didn't say what mould/load you are using.

[Lloyd Smale]

some more kind of weird things today. First I found part of my problem Two 20lb batches of bullets were not cured properly. I allways did a smash test and they passed that no problem. But advice from others on here had me doing a scratch test which they failed and I found powder clumped on the bases like you would with tumble lube so the powder is reacting to the uncured pc and one batch that just pulling the bullet pealed all the pc off where it contacted the neck. Odd they passed the smash test but it sure proves that test isn't really valid. Found another weird thing. Had some done in smokes mustard that did pass the test. Funny thing is the checks fell off the bases in the necks EVERY time. The other uncured bullets would loose them about 50 percent of the time so that kind of reinforces my belief that the pc does not help hold a check on if you pc over your gas checks. I think my problem with the uncured bullets came from doing it in the cold winter. My oven probably just wasn't getting hot enough. I put my smoker temp probes (3 of them) all in the oven and found that 420 is just right to get 395-415. I preheated the oven and then baked for 30 minutes and they passed the scratch test and the smash test. I found 12 gas checks in the cabinet that must have fell out of the boxes. I seated 6 on already pc'd bullets and 6 on bare bullets then pced them. It was harder to pull the checks off the bullets when I put the check on after the pc was cured. I would guess the check crimps into the pc a bit and I still believe theres something going on with heating and cooling two dissimilar metals. Who knows! Well at least im about half way done with pulling down ammo and recasting all the bullets.

[Winger Ed.]

I wonder if they'd act any better with the Hornady crimp on gas checks.

I don't powder coat, but I've never had one come off without really getting violent with it.

[popper]

Few yrs back a fellow didn't crimp GCs - found one in the barrel - it does happen I guess. I've not seen any GC on the ground, shot at a range with concrete floor to 25 yds, not a GC in sight (308 & 30/30) used hornady & HF red. Local range is cut grass & I've never seen a GC there either. Is you shank too small? I've used a bunch of Cu GC from a member on 30/30 fast loads, none lost. Might try annealing some with a torch, then install. My normal alloy is much harder than yours, still no problem. I did have trouble with HiTek outgassing and popping the GC off during cooking.
Larry & Tim had a discussion about the problem a couple yrs ago. Tim recovered some and found the shank longer & smaller OD. Larry changed from lino to #2 and problem stopped. I proposed that the friction of Cu is greater and pressure of firing softens the alloy base. Basically stretching the shank. 296/297 is still pretty fast and pressure drops quickly - boolit outruns GC?

[Lloyd Smale]

If by other member you mean blamer he sells gator checks. Ive used them for years and never had a problem with them falling off. When I bought this batch from sage he was out of gators and I bought checks that he manufactures. Are they different? I don't know. I know that right after I crimp them on even the hard alloy coated or bare they are hard to get off and I cant imagine pulling the bullet out of a case just the neck tension would dislodge them in the neck of the case like Im seeing. But it seem that once they go in the oven it changes something. The bullets I put a second coat of pc on ALL pulled off and felt like there was no resistance to them coming off a bit. No on a unheated check crimped on a bare bullet or a coated bullet you have all you can do to pry them off with a knife and if any thing the ones crimped on an already coated bullet seemed harder to pull off then a check crimped on a bare bullet. this was with the 18bhn alloy or the really hard alloy I was using at first. I don't really think its a matter of a check biting into a softer alloy better I think it might be a expansion and contraction difference between a harder and softer alloy that makes them even more likely to get loose with harder alloys. think about what you do if you want to take a pressed bearing off a shaft. You heat the bearing and it expands and comes loose. When you heat a bullet in the oven im sure that gas check gets up to 400 degrees much faster then the lead bullet does. It would be about like taking a conventionaly lubed and checked bullet and putting the torch to the gas check. My guess is it would get loose real fast. What happens when you heat a check. It anneals it and makes it softer. It is also making the part of the check that is the crimp ring softer too. Add to that that it might not cool and come back to its exact original size.

Is you shank too small?

I would say no. These checks fit about perfect. Ive seen checks that you could just sit on a bullet still crimp to the base. Yes ive seen a few like that that have fell off but nothing like what im seeing here. These checks take a firm push of the bullet to seat on the bullet before sizing and look perfect once sized. As a matter of fact after taking the few sage checks that I questioned were different then gators yesterday and crimping them on bullets id have to say it isn't a problem with the sage checks vs gators. The initially go on nice and tight. Its not till a trip in the oven that the problem arises. I think ive learned at least 3 things here so far. Don't cook bullets in zero temps in an oven it the garage, Make sure your oven is getting up to a minimum of 400 degrees and let them cook. Don't get to anxious and take them out after 10 or 15 minutes. Give them a half hour. If your one that has to open the door and look id go even longer. Third is I wont gas check a bare bullet then bake if the check will fit on a coated bullet after its baked. I also learned that the smash test gets you a smashed bullet and that's about it. Do a scratch test and sit your bullets in a dish of powder to see if the powder reacts and for sure do this before you've loaded over a thousand rounds of ammo you have to pull down!!!!!!!!

[badgeredd]

Have you tried annealing the gas checks before you install them? Perhaps annealing the checks would alleviate the loosening of the checks, but I don't know that to be a fact.

I use the hi-tek coating. I coat the bullets, install the gas checks and size the bullets, then re-coat the bullets. Cure the coating one more time and water drop the finished bullet directly from the oven. I haven't had any trouble with losing the checks. BUT I am using a different coating!

One thing I am mindful of is losing the gas checks once they leave the barrel could damage my can. I DID have problems with aluminum coming off but never have had a problem with Gator or Hornady checks.

[Dragonheart]

When I have made checks out of roof flashing I annealed the sheets before cutting the checks as it softens the metal and makes easy cutting & forming the checks. I don't know if I could say the annealing process makes the check stay on better as that depends more on the proper fit. I will say not all bullet shanks are the same size and proper fitting of the check starts with the right thickness of the metal used in the check.

[Lloyd Smale]

I would say the fact that annealing makes the checks softer might make them easier to put on but less likely to stay on because the copper in the crimp would be softer too. Water dropping might have some merit because it would harden the check again. Only thing is if the temp differences already loosened the check because the two dissimilar metals expand and contract at different rates I have to doubt if the check is going to bit back into the bullet. I do know that your sure not getting much GLUEING ON effect with pc. the batch I put a second coat on that went through two cycles in the oven and were double coated made taking the check off as easy as a flick of a knife blade. Because pc is hard and very wear resistant doesn't necessarily mean pc has good shear strength. Look at super glue. It has great shear strength and can even work to glue on a check but try coating a bullet with it and see how it holds up to the abrasion of a barrel. Ones a glue and ones a paint. Even many glues have a relatively poor shear strength.

[Dragonheart]

LLoyd, what you are describing is the reason I am wondering if your coating has actually reached full cure.

[W.R.Buchanan]

Lloyd: Why don't you install the gas checks after you PC? Seems like the logical solution?

Randy

[Lloyd Smale]

LLoyd, what you are describing is the reason I am wondering if your coating has actually reached full cure.

I did find that a few batches of the bullets weren't cured. I was told the big test is the smash test and they passed it with flying colors but later I heard of the scratch test and the sitting a bullet in powder overnight and those batches failed miserably on those tests. Tells me the smash test just isn't a viable test for pc. Even if the bullets aren't cured properly theres still the problem of checks that were crimped on tight magicaly falling off after being cooked.

[Lloyd Smale]

I will for now on. I just got 2k of gator checks yesterday in the mail and have two coffee cans of bullets casted. My initial test was with a few sage checks I had left and they fit on a coated bullet fine and crimped on real well so for now on if the check will fit over the shank after its coated I will coat after pc'ing. Less work that way anyway. Before I had to run them through the sizer to install checks and again to size them after pc. This way they only need one run through the sizer

Lloyd: Why don't you install the gas checks after you PC? Seems like the logical solution?

Randy