Cannot crimp my gas checks onto Lee .312 160 grain boolits :(

[mojomandan]

Hello guys,

I have some nicely cast Lee .312 160 grain boolits for my mosin nagant. The driving band on the boolits measures to .312", which is the same as my mosin bore.

I made some gas checks from .014" thick aluminum flashing using a Checkmaker die set. After some difficulty tapping the bullet's base onto my bench to seat the tight gas check, I then ran the boolits through my Lee .314" lube and sizer die. The diameter of the boolit base with the gas check on runs about .320", so I figured my .314" sizer should do the trick. After running my boolits through the sizing die (and, I do feel resistance), I can still easily pull the check off with my fingers. If I run the boolits through the die upside down (check end first), the nose of the bullet gets deformed.

I even tried the crimping die from my die set to squeeze the check on, but the results are the same.

I am really disappointed...I was really looking forward to shooting these. What can I do?

[BK7saum]

Try annealing the check to get rid of some springy-ness. Plain base checks will not lock onto the boolit like hornady copper checks.

[Larry Gibson]

Your home made GCs are slip ons just as the older Lyman/Ideal were. No reason not to shoot them as long as the seated bullet has the GC in the case neck. I shoot my own home made GCs made out of the same .014 aluminum w/o problem in my own MNs. Also a bajillion slip on GCs went down range long before the advent of "crimp on" GCs.

Larry Gibson

[mojomandan]

Hi Larry,

Thank you for the info. I will try them out within the next week or so and report back!

[Boolseye]

Making them out of heavier gauge aluminum will help. I use the heaviest stuff I can find for my NOE 316299, sized to .315". Only way it works. I think the AL I use is .316", maybe heavier. I even recall cutting some discs out of .024" copper. Man, that took some leverage.

[Latheman]

Ill be watching this thread as I just bought a .312 dia 155 grain Lee mold and have never used gas checks before.

[guicksylver]

I have both of the Lee 312 155 and Lee 312 160 tl, I have had no problem seat h checks on either.
Mine drop 312 and are sized 311.
I use gator checks or those from NOE.

Maybe harder alloy would give you slightly bigger boolits ?

[Windwalker 45acp]

it may sound silly, but how about trying a dab of superglue on the base?

[mojomandan]

Making them out of heavier gauge aluminum will help. I use the heaviest stuff I can find for my NOE 316299, sized to .315". Only way it works. I think the AL I use is .316", maybe heavier. I even recall cutting some discs out of .024" copper. Man, that took some leverage.

.316" aluminum? That's more than 1/4" Or, do you mean 0.0316" thick? If so, that's still some serious thickness!

it may sound silly, but how about trying a dab of superglue on the base?

Not a bad idea I may choose to revisit down the road...for now I have put some faith in Larry Gibson's response with the hope my checks will be sufficient as is.

[Motor]

mojomandan, Been there done that.

I use the same everything except I'm using Hornady copper checks that are close to .018" think. If you do the simple math you will find that even with .018" thick material you have zero crimp on the Lee base with the .314" size die. At least that is what I found.

I was fortunate enough at the time to have access to a milling machine so I set up and bored my mould to increase the base diameter. Now the checks fit tight using the .314" size die.

Measure your base diameter then add twice the thickness of your check material. If it doesn't add up to at least .316" I doubt you are going to get good gas check grip.

Motor

[quilbilly]

I was given 4000 old style Lyman checks in 22 caliber and had the same problem. Since they were the All-American price (free), I just started putting a dab of super glue on the bottom of the the projectile before sizing and never looked back. Sure it is time consuming but what can I say - I am cheap. A year later I was given (paid $1) 1500 similar 30 cal Lyman checks and am doing the same with those and saving my modern crimp-ons for later.

[Boolseye]

Sorry, meant .016" Aluminum. Works great. And yes, I did punch some copper checks with .024" once.
Keep in mind the concept here–say you have a .283" shank. If you use .014" checks, the max that can get you too is .311" (.283" + .028"=.311"). Therefore, thicker metal is necessary when sizing for oversized bores. Also, too-thin checks may just fall off if they can't clamp on properly. Obviously there's a little wiggle room here on either side.

[Duckiller]

Super glue is the way to go. Had some checks that weren't staying on and the smallest drop of superglue solved the problem. Sizing and installing checks is not a speed contest so adding a dab of glue doesn't slow me down that much. There may be other ways to solve the check falls off problem but don't spend a lot of time trying to make some other method work when glue doesn't slow you down much and it works.

[Boolseye]

I picked up some Amerimax .016" aluminum from a member here.
I believe it will solve your problem if you can get your hands on some.

[Argentino]

it may sound silly, but how about trying a dab of superglue on the base?

I´ve done that for a while.

I´ve never had any problem when using slip on GCs that way (except for sticking my fingers from time to time) but I guess is not really necessary.

Argie.

[Motor]

I picked up some Amerimax .016" aluminum from a member here.
I believe it will solve your problem if you can get your hands on some.

They may or may not. I use the Lee 160gr TL as stated above and I could not get a Hornady gas check to crimp on using a .314" die like the OP is using.

My boolits are .284" on the check diameter BUT its because I modified my mould.

With his .314" die he will need at least a total of .316" So to use a .016" thick check he would need a base diameter the same as my modified boolits have. I doubt that his un-modified mould is making bases much larger than around .280"

Motor

[Boolseye]

yeah, you may be right. Seems the mold is a bit out of spec if that's the case.

[Motor]

I don't think the mold is out of spec. The boolit is intended to be sized to .309-.312

If you use a Hornady gas check it will crimp on using a size die within that range of sizes.

Motor

[Boolseye]

Yeah, you're right. I've owned three of that particular mold, however, and was able to do exactly what the OP wants to do with the first (old style) one. They were Hornady checks, perhaps it had a fat GC shank. The two I own now are new style, and I don't believe I've run any through the .314" from those molds..

[Motor]

Before I modified my mold the checks would all but be tight using the .314" size die. I had to work my way around them with my thumb nail and I could get them to walk off.

With my .311" size die they were tight. I very likely bored no more than .004" in diameter out of the mold.

I still use them when I size .311" in fact I even put them on with the .311" over powder coating and don't have any problems.

Motor