Plain Base Gas Checks

[161]

Where do you get Plain Base Gas Checks and can they be crimped with a Lee sizer?
Thanks

[161]

That explains why I'd never heard of them. I saw a post in cast boolit with a pic of one, looked interesting. Don't think I'll invest that much money right now. Thank for the reply.

[mrbill2]

I have seen them on sale on E-Bay.

[Doc Highwall]

If you put a gas check on a bullet that was not designed for it not only will it be harder to size the bullet causing distortion but the metal that is displaced from not having a gas check shank will also distort the bullet even more. Not to change the subject but have you ever wondered why shooters wanting to get the best accuracy pan lube their bullets. It is because the bullets do not get distorted buy being sized in a sizer die. When a bullet is larger then a sizer die and is pushed through, it swages the metal in the path of least resistance making it as round as the sizing die is. The best combination is a mould that casts a bullet of the right size, and is round that needs no sizing and can be pan lubed or put through a sizer die that does not size but only lubes the bullet. This is why it is great that we have group buys here at Cast Boolits getting a mould that drops bullets that fit our guns and require minimal sizing or non at all. When a new shooter asks questions somebody always says we need more information like what kind of gun, is it for light plinking loads or heavier hunting loads and what about extreme target shooting.target Then you will also be asked did you slug your gun. Then you will get a flood of answers.

[pistolman44]

Now you got me thinking. I too have a 45PB on order for a long period now. I see your point on distorting the base of the bullet. I heard the 35PB is working out ok.

[HollowPoint]

Unless the "As-Cast" size isn't a whole lot bigger than the size you're sizing down to, the distortion effect should be of no consequence; even with one of the gas checks in question.

Of course, if you're sizing down from say .434 to .429 or .430 all at once you may very well impart some distortion. (44 caliber example)

Since the inside diameter of your PB gas checks should be constant before installation, pre-sizing your cast bullets to the inside diameter of the gas check before you actually install it will mitigate the chance of distortion when you install your PB gas check onto your pre-sized cast bullet.

That's basically what you're doing even with a cast bullet that's designed to accommodate a gas check.

In a case like this, you may want to size down in steps till you reach your desired size.

I use lee sizer dies and I've not had any noticeable distortion on any of the bullets I've sized down.

Maybe I'm just one of the lucky ones.

HollowPoint

[Doc Highwall]

The thickness of the gas check say is .010" which means .020" all around on the base of displaced metal which will distort the bullet, and this is not even counting how much smaller you are sizing the bullet under it's cast size to begin with. It cannot be good for accuracy especially after doing all that work to cast the bullet in the first place. If it was a good idea it would be in the mould manufacturers catalog and all the moulds would be made with out the gas shank to save money.

[HollowPoint]

The thickness of the gas check say is .010" which means .020" all around on the base of displaced metal which will distort the bullet, and this is not even counting how much smaller you are sizing the bullet under it's cast size to begin with. It cannot be good for accuracy especially after doing all that work to cast the bullet in the first place. If it was a good idea it would be in the mould manufacturers catalog and all the moulds would be made with out the gas shank to save money.

I can't argue with that logic.

I just know that since I broke down and made my own PB check maker I've had none of the distortion or accuracy problems that are eluded to here.

I use aluminum flashing from HomeDepot that measures a little over the numbers you've mentioned above.

When I pre-size my plain bast cast bullets before installing them, any deformity-causing resistance that is present, is usually just on the gas check itself as it's being swaged into position onto the base of my bullet.

Since the gas check itself is hair under 1/8" in width, it offers little resistance for me as I push it through my sizing die. The rest of the bullet is just centered by the inside diameter of my sizing die because it had already been sized to that diameter.

Any accuracy problem I did have with these same bullets were experienced before I started installing these PB gas checks; and that was done as an afterthought.

If I hadn't gone the PB gas check route I would have lost money by buying a mold that wasn't working for me before the gas checks.

Of course, I'm only referring to one plain base bullet mold shooting out of one specific gun. Everything stated about possible in-accuracy caused by possible deformities caused by installing these PB gas checks may very well be the case with someone else's bullet mold and gun setup.

HollowPoint

[mold maker]

I fail to see where making a cast boolit round and moving a small amount of base metal to add a check will hurt its accuracy. After all we expect the throat and barrel to change the shape, size, and fit of the "perfect boolit". Melt, mold temp, and alloy all can change our boolits more than adding a check, even to a PB boolit.

[HollowPoint]

mold maker:

I failed to see the logic in that as well but, I figured that offering up an argument to the contrary would have only opened up a can of worms.

When I was casting .224 bullets, (before I gave it up) I actually did manage to deform several of them while sizing; and they were made with the gas check shanks on them so, I guess in some sense it is possible to run into deformation problems; which in turn would lead to accuracy problems; if you were inclined to shoot those deformed bullets anyway.

The only plain base bullets I cast and add these PB gas checks to are the .44 caliber round nose bullets from my Lee six cavity mold.

Since adding those gas checks I've never had a problem. I really must be one of the lucky ones.

HollowPoint

[Doc Highwall]

I am not saying you cannot get some accuracy with doing what you are doing for close range, but if you were trying for small groups at 200 meters for silhouette shooting it would become apparent. The bullet on a revolver should fit the cylinder throat. If you had a 44 mag and the front of the cylinder/cylinder throat measured .432" to get the best accuracy your sized bullet should measure at least .431" to a max .432" and hopefully this is larger then the barrel.

[Doc Highwall]

HollowPoint, if your LEE mould was casting undersized your gas check would help in this case. The real problem is you are fixing a mistake that should not be there in the first place. But you did make something that was not usable to something you can get by with.

[longbow]

Here is an article on the original Freechec tool.

http://www.lasc.us/TaylorFreeChec.htm

[JonB_in_Glencoe]

longbow...a great read...

Doc,
one use that I seek with a .004 popcan PB gas check is,
I have a PB keith style HP that I like to cast with a
softer alloy...a gas check will let me bump up the pressure
for a given alloy.
Jon

[RU shooter]

If you want to size it on using a lee sizer (my route also) stay with the thinner can material ,They go on nicely sizing the proper nose in first way on 35 cal plain base bullets. the thicker .008 and .010 material would actually turn inside out unless I sized reverse base first. And dont worry that thin material works just fine I loaded them up to full power jacketed levels in my 35 Rem. with good accuracy using a saeco #351 bullet.

[Doc Highwall]

JonB_in_Glencoe, I agree that a soft alloy is a good reason to use a gas check especially if they are for hunting and some practice where you do not shoot a lot of them. I have some moulds just for this, I just bought two moulds from MiHec 462122 one plain base and one gas check. I want to use 30:1 to 40:1 alloy and I will be able to shoot both side by side to get the accuracy I want.

[eagle27]

Perfectly formed bullet bases are generally accepted as an aid to good accuracy hence the production of nose pour moulds for this purpose. If gas checking a bullet then the same reasoning will apply to gaining accuracy i.e. a nice square and properly sized base gas check.

I run a shoulder for a .429" (44 cal) gas check on my plain base .423 cal bullets in a lathe. Can process these quite quickly and simply with the set up I have. They crimp on perfectly in the Lyman 450 with a good flat concentric base resulting in a poor performing bullet becoming a great shooter with the addition of a gas check.

http://i606.photobucket.com/albums/tt146/Lindsayb_01/collet003.jpg

http://i606.photobucket.com/albums/tt146/Lindsayb_01/400grcast002.jpg

[.30/30 Guy]

I guess that it is time for me to comment on the plain base gas checks.

I have been using one of Pat's 35 PB Checkmakers. My experience has been limited to using them in a .357 magnum. I have tested two different boolits in three different guns with the same results. The guns are a S&W model 27, a Merrill Sportsman, and a RPM XL.

My tests have been to use the same load of 2400 with each boolit with and without the PB checks. Each gun shot smaller groups with the PB checks.

I have been surprised at how easy the PB checks go through my Star sizer.

I have used .004 pop can through .010 copper for the PB checks. I did not see that the copper material checks took much more effort to size than the pop can stuff. My favorite PB check is the .008 lith plate material.

[Ausglock]

G'day.
What is the dia of the disks used to make the 35 cal GC?
I'm thinking of trying some in my 357Sig on a Lee 356-125-2R.

Thanks.,

[WILCO]

G'day.
What is the dia of the disks used to make the 35 cal GC?
I'm thinking of trying some in my 357Sig on a Lee 356-125-2R.

Thanks.,

Best WAG: .4531 using a 29/64 drill rod and .016 aluminum material.


http://www.tmtpages.com/LinkSkyImages/forum_images/Gas_Check_Dimensions.gif

Machinist drill sizes: http://www.engineersedge.com/drill_sizes.htm

[PatMarlin]

The thickness of the gas check say is .010" which means .020" all around on the base of displaced metal which will distort the bullet, and this is not even counting how much smaller you are sizing the bullet under it's cast size to begin with. It cannot be good for accuracy especially after doing all that work to cast the bullet in the first place. If it was a good idea it would be in the mould manufacturers catalog and all the moulds would be made with out the gas shank to save money.



If you put a gas check on a bullet that was not designed for it not only will it be harder to size the bullet causing distortion but the metal that is displaced from not having a gas check shank will also distort the bullet even more.

I have to disagree with some of the comments.

I have found no evidence of distortion whatsoever with my PB dies. Sizing a PB check is effortless, and again does not distort. Results from many of my customers have shown far less leading, and increased accuracy with smaller groups in identical side by side boolit testing.


If you attempt to use to thick of a material for PB checks, boolit alloy that is tempered to hard, and sizing a large diameter reduction then yes- you will have some problems.

1. Use inexpensive AL or copper .004 to .008 gas check material that is not tempered to hard.

2. Size and check your bullets within the same day as casting if you are running harder alloys. I have had no problems with WW air cooled alloy, no matter how old.

3. Don't try to size less that .002 under cast diameter all at once.

4. Lube your boolits with Ballistol, or boolit sizing (case) lube before sizing.

5. Make sure the entry lip on the dies have a smooth transition.

[taminsong]

30/30Guy: I have been surprised at how easy the PB checks go through my Star sizer.

Sir, please explain, if possible in details how you do it? I have a hard time sizing bullets in my Star with 35PB Checks. I used the Lyman4500 to do it.

[Boerrancher]

I have a PB check maker for both the 357 and 429 dia boolits. I don't shoot super heavy loads out of my hand guns, because I always figured if I needed more than about 1100 fps, I needed a rifle. I only really noticed a difference between with and with out checks when I shoot them out of my rifles. My Micro Groove Marlin 357 mag, prefers the checked boolits a bit better than just a plain based boolit, and my old 44-40 Win didn't seem to have much of a noticeable preference. It did shoot the checked boolits a hair bit better off the sand bags, but I don't think there would be a difference when shooting in the field.

Best wishes from the Boer Ranch,

Joe

[.30/30 Guy]

taminsong:

All of my pistol boolits that I have used PB checks on are cast with a mixture of half lead and half wheel weights - air cooled. The boolits are not much larger than the sizing diameter. I am from the "old school" - I size all of my boolits base first with my Star.
I have tried pop can material for my checks but find it a real pain to cut the strips and punch the disks. My prefered PB check material is 0.008" lith plate followed by 0.0085" aluminum and then 0.010" copper. All seat without much requiring much pressure.

[reloader28]

Except for hunting boolits, I use straight WW lead to simplify when I collect and remelt my used boolits.

My brothers 9mm gave us fits. I tried different sizes, powders, loads, heat treat, everything we could do and we still had lead in the barrel.

With Pat Marlins PB checkmaker I can use free pop cans and now we can actually run full power loads in 9mm and have zero lead in the barrel with good accuracy.
This thing is a 9mmer's dream.

My friend and me were shooting full power 357 mag a couple days ago with air cooled WW. He had boolits plain based and I used the same boolits but with a check. We both had some lead without the checks, but the barrels were spotless and accurate with the checks.

I lube and size in 1 stoke, then put on a check and run it thru the sizer again and have no problems. I aint seen any problems with distorting the boolit.

[Dannix]

taminsong:

All of my pistol boolits that I have used PB checks on are cast with a mixture of half lead and half wheel weights - air cooled. The boolits are not much larger than the sizing diameter. I am from the "old school" - I size all of my boolits base first with my Star.
I have tried pop can material for my checks but find it a real pain to cut the strips and punch the disks. My prefered PB check material is 0.008" lith plate followed by 0.0085" aluminum and then 0.010" copper. All seat without much requiring much pressure.
That's a new one for me. Could you share your source for that? Thanks!

[.30/30 Guy]

If I remember correctly I got the 0.008 lith plate material from JKH on this site. Great material and service.

[carlsonwayne]

Would anyone be interested in sending maybe 10 or 15, 35 cal. PB checks, so I can see them and try them?? I really want to get the dies, but since I can't seem the grasp the concept, it would help if I could see and "install" some. I shoot a lot of 9mm, so that is what I would buy first. I would appreciate it a lot if someone would be so kind.

[161]

Would anyone be interested in sending maybe 10 or 15, 35 cal. PB checks, so I can see them and try them?? I really want to get the dies, but since I can't seem the grasp the concept, it would help if I could see and "install" some. I shoot a lot of 9mm, so that is what I would buy first. I would appreciate it a lot if someone would be so kind.

PM sent
161

[Dannix]

If I remember correctly I got the 0.008 lith plate material from JKH on this site. Great material and service.
Thanks! I'll look him up.

[carlsonwayne]

Thanks 161, I'll let you know when they get here. It took me a bit to find this thread again.

[carlsonwayne]

They came today. I'll PM you in case you don't see this. Thank you so much!!!!!!

[JonB_in_Glencoe]

bumping this thread to the top.

[MaxJon]

I really love the popcan check idea! Might have to buy a .25 cal PB mold, and try them in my 25 303!

[bld451]

Me too. Just loaded these and hope to do an initial test this week. Been PC'ing some supersonics for the 300 blackout and have not had any leading but noticed on some recovered bullets the bases were gas cut pretty badly. All that culling for base defects to no avail..... anyway, gonna see how these do. I just punched the discs with a 7/16ths punch we have at work, made a forming die out of some cold rolled, and voila! Well, it wasn't that simple.... I was in a hurry and didn't research as I ought to have. The first discs were 1/2" and were way too tall. I suspect when I make the hard die set for the press, it will be just over a .400 diameter disc. If this works out well, I think I'll be making sets for most of what I shoot. Been noticing some gas cutting on my 10mm and 45-270 SAA bullets too.

262035

262036first stab with .500 discs.

262037that's more like it.

So far, no problems seating base first in the Lee sizer except for 3 or 4 that were not quite square. Need to pay attention...

262038 this is what I'm trying to avoid.

[bld451]

Had a little problem catching my bullets yesterday, so put some cinderblock behind the rag box . These NOE 153 HTC's at about 1800 fps went through the gel block, my rag box and broke the cinder block, but I stopped them, by gosh. Not exactly apples to apples as far as condition but you can see the checks did what they were supposed to.
262185
262186
262187this is the 311410 MP hollowpoint at about 1950. Not MOA yet but accuracy was measurably bettern. Didn't find any checks on shanks but I haven't had any indication yet that they are coming off in flight.

Infact, I did find one off of a MP 235 that came off in the gel block and came to rest within 1/4" of the end of the block.262190

262191 pay no attention to those voids in the base of my bullet....

[dimaprok]

Infact, I did find one off of a MP 235 that came off in the gel block and came to rest within 1/4" of the end of the block.262190

262191 pay no attention to those voids in the base of my bullet....

Wow, I learned something. NOE HTC 153gr SP is very accurate with IMR 4198 both in my Ruger 300 blk and 7.62x40WT. I had 4 out of 5 shots at MOA. In limited testing I didn't notice the difference in accuracy with PB gas check and without. I am still firm believer in "regular" gas checks (homemade). These PB gas checks just don't grab over PC that well and tend to come off. Over bare lead they stay put well but the slick powder coat not so much. I prepared a batch from my new mold Lachmiller 130gr PB that looks identical to Lyman lyman 311410 with BLL lube and see if I can drive them at mild velocities 1800 - 2000 fps without leading barrel. Powder coated same weight NOE easily runs 2330fps with good accuracy this is with 7.62x40WT.

[dimaprok]

One more thing, I noticed you're you got a line that looks like crimp? Are you putting on heavy taper crimp or Lee factory crimp? I believe you should only put a bare crimp on lead bullets to remove flare.

[bld451]

One more thing, I noticed you're you got a line that looks like crimp? Are you putting on heavy taper crimp or Lee factory crimp? I believe you should only put a bare crimp on lead bullets to remove flare.

I have been crimping with the Lee F.C die. I tend to crimp all the 300 blk ammo I load. I should probably test it without a crimp to see if the bullet jumps when fed from the magazine. I presume it will since I only have about .001" neck tension. I have tried a lighter crimp but have not tried none.

262261these are what I have to compare right now. Bottom (left if you can read the targets...) set is with PB gas checks. Right is bare. Not quite at moa yet but improving. That little 311410 hollowpoint surprised me a little. I thought it would just come all apart. The nose did but the base (73 grains ) went through the 16" block. Permanent cavity maybe 6" long . Great coyote medicine. That was at 1900 fps out of my 8.5" blackout.
262262

[dimaprok]

My understanding and same thing comes from manufacturer of Barry's copper plated bullets is that you should crimp just enough but not to perforate and compromise the coating. I believe same applies to powder coat, I crimped only to remove the flare, maybe light crimp at most. P.S. You might like these printed targets better http://www.mytargets.com/ I like to print them on thicker paper too, you get cleaner holes; 4 - 5 per sheet is optimal and one per page for sight in.

[bld451]

My understanding and same thing comes from manufacturer of Barry's copper plated bullets is that you should crimp just enough but not to perforate and compromise the coating. I believe same applies to powder coat, I crimped only to remove the flare, maybe light crimp at most. P.S. You might like these printed targets better http://www.mytargets.com/ I like to print them on thicker paper too, you get cleaner holes; 4 - 5 per sheet is optimal and one per page for sight in.

Thanks. I like their selection. Right now I'm using the single pistol bulls because they fit my 1x red dot well. (Easy to center) and I'm shooting different bullets that have different points of impact. That target seems to catch them all without sight adjustments. I thought about putting a higher mag scope on it but shoots pretty well with 110 varmageddons with that 1x and blank sheets of paper at 100. Right around MOA. I'll be pleased with that when I get there with these.

Funny, I started this with the intent to shoot a lot more with cheaper ammo. Ha... I'm waay down the rabbit hole now..... hoping I can nail this down and load a bunch of ammo that is the same, sight in and have some fun. Had things pretty good until the p.c., 300 blk cast and pb checks came to mind. Now it's all testing. Can't wait to bump around in the woods with these loads.

I'm going to try the MP 311410 as a solid with 20:1 and see what that does. I'm pleased to see there is no skidding with 50/50. My 45 colt and 10mm are skidding and gas cutting but not leading. (?) The Colt groups 1.5 or less at 25. Pleased with that but I'm going to try the PB checks on those two and see what I get.

I'll try the no crimp situation too. I just figured I'd have to. Better find out.

[bld451]

Also going to try these.

262370

Got this mold as a second from LBT. It's a 200 gr 38 Kieth swc. Had a small gouge in one of the lube grooves, and I never took a liking to it as I thought I would. It sat neglected for a few years. Well, plain base gas checks and powder coating resurrected this mold. My wild hair told me to machine out the lube groove, so I did and just left enough of it to clear rifling. Now they are matchy-matchy and ready to test. I made this checkmaker today and a bunch of.500 discs from a Monster drink can. The two checks I'm currently working with are made with standard 7/16ths and 1/2" punched discs so one less piece of equipment I have to make right now. Tonight I formed up a few and they are great so far. I can get them on easily, they are just tight enough that they don't fall off on the way to the press, and they crimp on pretty well. I have to try pretty hard for a bit to peel one off with a fingernail. They all went on nice and straight, too. Can't wait to shoot 'em!

262371

262372

[Castloader]

Also going to try these.

262370

Got this mold as a second from LBT. It's a 200 gr 38 Kieth swc. Had a small gouge in one of the lube grooves, and I never took a liking to it as I thought I would. It sat neglected for a few years. Well, plain base gas checks and powder coating resurrected this mold. My wild hair told me to machine out the lube groove, so I did and just left enough of it to clear rifling. Now they are matchy-matchy and ready to test. I made this checkmaker today and a bunch of.500 discs from a Monster drink can. The two checks I'm currently working with are made with standard 7/16ths and 1/2" punched discs so one less piece of equipment I have to make right now. Tonight I formed up a few and they are great so far. I can get them on easily, they are just tight enough that they don't fall off on the way to the press, and they crimp on pretty well. I have to try pretty hard for a bit to peel one off with a fingernail. They all went on nice and straight, too. Can't wait to shoot 'em!

262371

262372

I'm wondering how this went, I know it was 2 years ago. I'm contemplating doing nearly the same for 9mm. I'm primarily interested in what kind of accuracy you got with them.