Sizing gas check boolits

[1Iron]

I've been casting gas check boolits for over 40 years. I have always sized the same as plain based boolits. I read something recently that made me wonder if I have been sizing incorrectly all these years. Your thoughts on the subject, please.

1Iron

[Lakehouse2012]

I've been casting gas check boolits for over 40 years. I have always sized the same as plain based boolits. I read something recently that made me wonder if I have been sizing incorrectly all these years. Your thoughts on the subject, please.

1Iron

Maybe site what it was that you read and how it's different from the way you're doing it.

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[charlie b]

When using a lube sizer I set the GC on the bullet base then put the bullet in the sizer. When sizing for powder coating I set the GC on the bullet and set it on the ram, sizing nose first.

[fordwannabe]

I snap the gascheck on the base then size GC end first.

[1Iron]

My question was vague. What I am wanting to know is, do you size to the same the bore diameter or .001" over using a gas check?

1Iron

[Lakehouse2012]

My question was vague. What I am wanting to know is, do you size to the same the bore diameter or .001" over using a gas check?

1Iron

I size at least. 001" over, sometimes. 0015 over for 9mm

My process on GC has always been snap the check on first and then nose first through the die.

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[Hick]

I still size 0.001 over with a gas check. Is it necessary? I don't know. I go all shooting season and only run a bore snake through the bores between sessions-- one real cleaning every winter. The bores don't lead so I keep sizing 0.001 over. never tried sizing to the bore so I don't know if it matters. For me it's a simple case of "if it ain't broke don't fix it."

[stubshaft]

I've been sizing .001" oversize with a gas check for over 50 years. I do not plan on changing that because someone wrote an article!

[Bazoo]

I usually begin by sizing .001 over the norm regardless of gas check or plain based. I most always test bullets as small as groove diameter and as large as I can get/make, checking both accuracy and leading.

My Winchester 92 44 Magnum has a groove that is .4302 across one section and .4295 across the other 2 sections. I haven't experimented with sizes for accuracy yet, but I had some 44 Special loads made up with .430 sized bullets that I have fired and didn't have any leading. Accuracy was plinking good, and made a "group" on paper with an expedient field rest at 30 yards. I have a lot more testing to do, but it shows promise right out of the gate.

In my Winchester 94 30-30, I haven't done much testing, but I found good results almost immediately with bullets sized through my .310 sizer that come out more like .3098. I get right at 1 5/8" groups at 70 yards (my table was set at 70 yards) with my better loads, and preferred factory loads will do 1 3/8".

[Shopdog]

I almost universally test to see what the rig prefers... as cast,001 over,or 2 over. Rarely more. Most of my hotrod rifles like as cast with just the GC "area" sized(even this has a height/depth range). Can't say I ever had an undersized mould.....

Until very recently;

Snagged a RCBS .30 165g sil mould off evilbay. P.O. sent a short note saying it was his late dad's and he finally got around to selling a bunch. By this correspondence,I'm guessing the mould is late 90's to early '00's? Just to put a date on it.... Well,try as I may,could only get it to a just barely .300 nose,and .3085 body. I make/use tapered nose dies and this mould is dropping 3 to 5 "tenths" out of round so the nose being a touch small was problem #1. #2 was as cast @3085 but that's again with a range of .3082" on the "low" side...being out of round. Using our vertical impact tester I was able to put some #'s on what ot takes with each alloy to bump the little bugger up to a good proper fit. Luckily the 30-06 rig it was to be abused in was a new Shilen with a nice tight'ish bore. Through testing,it was determined how much,kick in the butt the lubed bullet was gonna need. Which eliminated a BUNCH of shoot testing,and any notion of "low node" stuff.

HEALTHY dose of IMR4350 was used,and durn if the 1st,well pondered load just started to shoot dots.

Point of this rambling is;

Ultimately,testing each particular mould..
in each rig for not only diameter,but a host of other metrics is going to produce the answer. Good luck with your shooting.

[charlie b]

So, yes, I size GC bullets using same die as plain base. Mine are .309.

[Mr Peabody]

I size gas check bullets the same as plain base for my .357

[1Iron]

Thanks everyone for your responses.

1Iron