10mm hardcast w/gas check help

I'm loading new Starline brass. Ran through my Hornady sizing die.
Longshot powder 7.8, 8, 8.2 grains. 5 rounds each.
CCI large pistol primers.
Lyman flaring die.
Montana Bullet Works 200 grain https://www.montanabulletworks.com/p...-200gr-wfn-gc/
OAL at 1.25"
Finished with Lee FCD to remove flare.

As a quick check, I did a "plunk test" using my S&W M&P 4.6" 10mm barrel.
They drop in easy, but I can't really tell if the bullet is interfering with the bore. They need just a light tap of my fingernail to drop out of the chamber. I also pushed as hard as I could on the cartridge into the chamber with my thumb and cannot see any deformation or marks on the bullet. Am I possibly having them stick a bit on the bullet lube that pushed out of the mouth during seating?

Any thoughts or advice?

Could be. Wipe a few clean with a paper towel and see if any difference. You could also give the Lee Factory Crimp Die a little adjustment to further reduce the flare. I assume your barrel is clean of transferred lube. Does your slide go into battery with these rounds? If so, I'd shoot 'em.

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Originally Posted by 725

Could be. Wipe a few clean with a paper towel and see if any difference. You could also give the Lee Factory Crimp Die a little adjustment to further reduce the flare. I assume your barrel is clean of transferred lube. Does your slide go into battery with these rounds? If so, I'd shoot 'em.

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I'll clean and check. I haven't been to the range. I was loading on this WY blizzardy day. I haven't tried chambering yet. Lot's to do. Thank you!

ETA: I wiped the cartridges off pretty well with a towel and most plop right out when the barrel is inverted. I "think" I'm good to go?

Your loads are passing the plunk test ... as long as they drop in and then are "easy out" , a gentle nudge is fine ... it's probably just boolit lube ... They aren't sticking hard ...
I would say you are good to go ...

So ... go CHOOT EM' !
Gary

Yup go shoot them.

Well, the chronograph tells me I'm not hitting 1200 fps. About 1130.
I ordered some of the same bullet sized to .401. Not sure if that will help or not.

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Originally Posted by czgunner

I'm loading new Starline brass. Ran through my Hornady sizing die.
Longshot powder 7.8, 8, 8.2 grains. 5 rounds each.
CCI large pistol primers.
Lyman flaring die.
Montana Bullet Works 200 grain https://www.montanabulletworks.com/p...-200gr-wfn-gc/
OAL at 1.25"
Finished with Lee FCD to remove flare.

As a quick check, I did a "plunk test" using my S&W M&P 4.6" 10mm barrel.
They drop in easy, but I can't really tell if the bullet is interfering with the bore. They need just a light tap of my fingernail to drop out of the chamber. I also pushed as hard as I could on the cartridge into the chamber with my thumb and cannot see any deformation or marks on the bullet. Am I possibly having them stick a bit on the bullet lube that pushed out of the mouth during seating?

Any thoughts or advice?

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Hogdon recommends a maximum of 7.5 grains with a 200 grain bullet. You are already well over that. I think you need a different powder and to stay within specs.

https://www.hodgdonreloading.com/hod...dgdon-longshot

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Originally Posted by Tall

Hogdon recommends a maximum of 7.5 grains with a 200 grain bullet. You are already well over that. I think you need a different powder and to stay within specs.

https://www.hodgdonreloading.com/hod...dgdon-longshot

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Thanks. I found so much conflicting information. Do you have a powder you recommend?

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There are several mentioned here:

https://www.handloadermagazine.com/10mm-auto-pet-loads

I would stick to manufacturer's recipes and use perhaps Unique powder or AA#5.

Try Here:

https://www.hodgdonreloading.com/rel...c=true&type=53

You need to get a copy of the Lyman Cast Bullet Handbook 4th edition .
Under the heading of 10mm Auto there are 6 different boolit weights and under the 200 gr. boolit loads with about 16 different powders ... and the data is reliable .

Hodgdon's reloading data center is sketchy at best ... I no longer go there for data .

Gary

Alotta guys like longshot. I know most run past book to hit proper 10mm numbers. WORK UP EASY!!!!

I use blue dot but again WORK UP EASY!!

Today I been using POWER PISTOL. Easy to pass 1200 in my G20. 1260 in my G40. Same here yes past book GO SLOW has been fine.

10mm has been neutered and continued to be neutered. Even data is pusified cause well lawyers thats why! Know your work. Watxh for signs and GO SLOW!!

Blue Dot is a good choice. I also like AA#9. I can get about 1350 with a 180 grain cast (GC) boolit in a 4" GP100 and a little north of 1400 fps in my 5" 1911.

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Originally Posted by cwlongshot

Alotta guys like longshot. I know most run past book to hit proper 10mm numbers. WORK UP EASY!!!!

I use blue dot but again WORK UP EASY!!

Today I been using POWER PISTOL. Easy to pass 1200 in my G20. 1260 in my G40. Same here yes past book GO SLOW has been fine.

10mm has been neutered and continued to be neutered. Even data is pusified cause well lawyers thats why! Know your work. Watxh for signs and GO SLOW!!

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I too use Power Pistol and also Winchesters Auto Comp.

I don't have a lot of trigger time with any 10mm platform, but 200 gr. @ 1130 f/s is NOT "slouchy" performance! If you can obtain similar performance with a faster-burning (thus, more economical) propellant, all to the good! If not, then then 8.0 + 0.2 gr. per load is not a bad deal.