Square, Flat Gas Checks & Round Bullets

[Boomer Mikey]

To make match grade cast bullets I "iron out gas checks" and flare the mouth of the gas check to prevent shaving lead during the crimping process.

I made a flaring/flattening punch with a 15 degree taper and use my drill press as an arbor press to flatten and flare gas checks.

http://www.cnczone.com/gallery/data/9030/medium/Expanding_Gas_Checks1.JPG


On the left gas checks as they come out of the box. On the right gas checks flattened and flared with the punch in the middle.

http://www.cnczone.com/gallery/data/9030/medium/Sizing_Lyman_311041_Bullet_-8.JPG http://www.cnczone.com/gallery/data/9030/medium/Sizing_Lyman_311041_Bullet_-9.JPG

Then I seat the gas checks and size the bullets nose first in my Saeco bullet sizer/lubricator using a custom made flat face nose punch that is the exact size of the die. Before/After sizing.

http://www.cnczone.com/gallery/data/9030/medium/Sizing_Lyman_311041_Bullet_-3.JPG

You can see the difference in how flat and sharp the corners are between these two groups of bullets. On the left - sized base first; on the right - sized nose first.

Now the bullets can be heat treated then lubricated the normal - base first method - with a sizing die .001" over the size of the sizing die used - in this case .310".

Sizing the bullets nose first in a Saeco sizer virtually guarantees perfectly round bullets as the dies have a long lead into the final size of the die and the nose of the bullet will center itself in the die.

One of the draw backs to using the superior quality Saeco sizer/lubricator is nose punch availability for bullet moulds other than Saeco. I made an adapter to use Lyman & RCBS nose punches in the Saeco as seen in the picture; however, I usually lube bullets with an RCBS lubricator/sizer anyway.

Boomer

[Gun-adian]

I use a Lee sizer to seat the gas checks then run them through an RCBS lubrisizer for lubing.

If I just use the lubrisizer I find the gas checks are at the very least rounded on the edges and usually slightly dimpled from any lube that gets under the bullet when sizing. Running them through the Lee sizer first keeps the bases uniform.

It's a two step process that takes more time, but it works for me.

Mike

[slughammer]

You can see the difference in how flat and sharp the corners are between these two groups of bullets. On the left - sized base first; on the right - sized nose first.


What kind of accuracy difference do you find on paper?

[Boomer Mikey]

What kind of accuracy difference do you find on paper?

I haven't tried to compare the two against each other yet. I did all of this to eliminate shaving lead on the base of the bullet when seating gas checks.

It sounds like a good excuse to make a trip to the range.

Boomer

[arkypete]

First thing I do with a new box of gas checks is throw them into an old skillet, turn up the heat on the stove until the checks begin to turn black and set them aside until they cool.
I use my Lyman sizer/luber like an arbor press, using a flat nose punch and a piece of flat steel on the bottom to seat the gas check firmly. When done seating all of the checks in that batch, then I size and lube the bullets.
All gas checks are square, flat and usually still attached to the base when dug out of the berm. If they gas check has separated from the bullet base it's because the bullet pretty well deformed from impact.
Jim
Jim

[Bass Ackward]

Boomer,

I used to be anal about this until an ol' gentleman pointed out that no matter the method you use or the type of sizer used, all bullets are sized nose first in the ways that counts. And that the pressure used there will seat any check flat and square as it and the base becomes one.

His only ritual was to anneal to avoid spring back.

Report your shooting results when you can.

[Boomer Mikey]

I wasn't pickey about sizing bullets nose first or about how flat and sharp the corners are on the base of the bullet until I tried the nose first routine on some 325 grain plain base bullets for my Marlin 1895 CB. The difference on paper was an amazing 50% reduction in group size.

I like the Lyman 275 grain F N 44 cal bullet in my Smith and Wession 629 DX Classic for handgun silhouette and never could get that bullet to center itself in the sizing die base first. It would always be off center. When sized nose first they are perfectly centered. Then I got a Saeco sizer and die to see if I could get better results. The Saeco dies produce superior results with this bullet and noticeably reduced the fliers.

I only "iron" the 30 caliber gas checks as they are the only ones I'm having problems with.

Boomer

[357maximum]

I believe what Bass is saying is the Gospel on this:::::

I cannot prove it, but I imagine about the time you pull the trigger all gas checks get seated pretty firmly and pretty consistently...just a thought.....I too have way overthought this a one point or another, and I personally find that if the checks are annealed anything else you do to them is a waste of time...

Michael

EDIT: I cannot even spell my name correctly, what the ell.

[Jumptrap]

I have always applied the advanced reasoning methodology....apply gascheck, run throu sizer so it doesnt fall off. Load and fire.......15,000 to 30,000 psi later, gacheck firmly attached, square as the base is/was and it's purpose met and then discarded.

I have read all sorts of comments as to whether the check stays on or flys off and how this anomoly affects accuracy. I have recovered hundreds of bullets with the check still in place....but the vast majority of bullets are never recovered. However, on or off....the holes in the target all seem to be arranged in a regular and acceptable pattern. So, WFD does it make if the stay on or fly off? I can't answer that question definitively and really, don't give a ****.

[357maximum]

So, WFD does it make if the stay on or fly off? I can't answer that question definitively and really, don't give a ****.


Jump,

Exactly how I feel NOW, I wish I had come to the simple truth earlier in life, but sometimes everyone just plain overthinks thaings. I will guard the chrony though, never give it a thought, but I will guard it with a small board from now on JUST IN CASE..my old man just bought a new beta and I would hate to F it up for him, he shot his old red box and it was not a good day for him, funny as hell for bystanders though...

As long as they all do the same thing 99.9 percent of the time IRDNGAFE....

Michael

[sundog]

Jump, me neither, give a rat's @$$, that is, all long as accuracy is acceptable. Except one time. Durn things were coming off as they approached the chrono. Smacked the start sensor, then the next one clipped the wire, then the next one..., holy $h*t, Batman! Over 4K fps out of a 25-20! ***O? Those were some old Ly checks. Won't use them again unless that's all I got left. And then, NOT over a chrono! A little solder and everything was back in order. sundog

[wills]

They look round to me.

[georgeld]

Sun dog:

A b/p patch will wreck one too!!

So will hitting those support wires. Replace them with wood dowels @ 4'/ dime, make's four or five per stick.