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OTShooter
05-20-2018, 04:40 PM
I’m looking ahead to the (near, I hope) future when I start casting bullets. I’m going to be casting a .30 caliber, 150-ish grain bullet for use with 300 Blackout, and the bullet is designed to use gas checks.

I will be powder coating my cast bullets. The powder coating process seems to be very well covered in a few stickies, so at the moment I don’t think I need any real guidance there.

I already have the Lee push-through sizing die, and the info I have found from Lee says that this die will allow me to seat gas checks. But they don’t say how that’s done.

So can someone give me a quick, basic tutorial on how you seat gas checks, in general and specifically with a Lee push through sizing die?

I have pretty well figured out that the bullets should be coated before seating the gas check, but I sort of need to know things like whether I need to do anything special to the base of the bullet when coating it, etc.

Thanks!

Outer Rondacker
05-20-2018, 04:56 PM
skip to 9 mins if you cant wait or watch it all and learn. https://youtu.be/nno2E1kFJJY

DAFzipper
05-20-2018, 08:57 PM
Shoot them without gas checks. I've never had a leading problem without gas checks, powder coated in 300 blackout

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OTShooter
05-20-2018, 09:50 PM
skip to 9 mins if you cant wait or watch it all and learn. https://youtu.be/nno2E1kFJJY
That was a very well done demonstration. Thanks for the link. I was clearly overthinking this. :oops:

OTShooter
05-20-2018, 09:50 PM
Shoot them without gas checks. I've never had a leading problem without gas checks, powder coated in 300 blackout

Sent from my LG-H700 using Tapatalk
I was under the impression that, if a bullet was "designed for" a gas check that it would not obturate the bore properly without one. So I've learned something new - again - this evening. Thanks.

Oily
05-21-2018, 05:03 AM
You can get gas cutting by not using gas checks with stiffer loads if your bore fitment is marginal. I would like to see the boolits standing up after gas checking in that video because he wasn't even snapping the checks on the boolit before sizing. You could clearly see some boolits were leaning as they entered the sizing die. IMHO boolits that won't start straight can have gas checks crimped on a little crooked and this is very detrimental to accuracy. I always snap or tap checks on in the case of powder coating before sizing to make sure the base of the boolit is as square as possible. In pistol calibers the base of the boolits are very important to achieve accuracy
o

odfairfaxsub
05-21-2018, 07:20 PM
Crooked gas checks took my 1 inch groups and made them 2 Inch groups

rsrocket1
05-23-2018, 04:53 PM
I was under the impression that, if a bullet was "designed for" a gas check that it would not obturate the bore properly without one. So I've learned something new - again - this evening. Thanks.

You don't need the base of the bullet to obturate. The body of the bullet will fill the grooves and prevent gas cutting if the bullet is wide enough. The problem comes with an uneven or crooked base. The gas check makes the base uniform. If your cast bullets look very uniform after PC'ing, you may be able to shoot them and keep your accuracy without a gas check. The only way you can test this is to make a couple dozen PC'ed bullets with and without CG's and test them out.

44Blam
05-25-2018, 12:40 AM
LOL! I have a rubber mallet, I always fit the GC and give the boolit a thump... Or 10 thumps... Until it's flat! :)

OTShooter
05-26-2018, 08:24 PM
You don't need the base of the bullet to obturate. The body of the bullet will fill the grooves and prevent gas cutting if the bullet is wide enough. The problem comes with an uneven or crooked base. The gas check makes the base uniform. If your cast bullets look very uniform after PC'ing, you may be able to shoot them and keep your accuracy without a gas check. The only way you can test this is to make a couple dozen PC'ed bullets with and without CG's and test them out.

So I'm getting that making sure the bullet is sized properly for the bore, and of course that the base is flat and even, may be more crucial than anything else. Good pour and sprue plate techniques should take care of the base, right?

Joe K
05-26-2018, 09:08 PM
I seat gas checks and push through the lee sizer before powder coating. After coating run them through the sizer again. This is an extra step but, I have more consistent results. Powder coating adds thickness and is harder to install the gas check square. I am using the shake and bake method for powder coating. Some folks spraying the coating have methods of leaving the boolit base bare. Hope this helps.