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I've been trying to shoot these 180gr plus bullets out of my 300blk with a 1/7 twist, 11.5 inch barrel, at what I think should be around 1300fps to 1400fps min load was 13.4gr Lil gun max was 15gr Lil gun. These bullets are a gas check design, however I ran them powder coated with no gas check. The mold I used was Ideal mold 309329 sized to 309. Most of the bullets did not hit paper at 50yrds, the ones that did flew sideways. Any ideas on what the problem might be?
I don't think your running them fast enough. I'm running a Lyman 311041, 173 grain gas check at 1750 fps. It is a track driver in both 300's we load it for. It's nasty on jack rabbits and prairie dogs from 75 yards in.
Put the gas check on. I've already been through this.
probably too slow.
or the gas check thing.
the 11" barrel ain't helping you a bit.
in my bolt gun I'm running the LEE 230 with 3.5gr of 700-x and they are plenty stable at 50 yds.
if I bump the load .2grs it shoots better, if I drop it .1 or switch to a pistol primer my groups triple in size.
sideways [keyholes] strikes are a function of non stability.
Wrong size, try bigger. GC will probably help with accuracy, not stability. This is from a 40SW, max load, almost pure alloy. Sideways are undersized. I beagled the mould to get the right size. I run my 1:8 BO 10" pistol with 170 PB at your fps, no problem.
Attachment 190266
Going to try the gas checks and slug my bore to see what size it is.
guess I should have mentioned I am running .310 diameter.
the above was to show you can go super slow and be stable [and ramp things up and still be accurate]
you have to get the fitment right in either case.
Slugged the bore at .309 going to try some sized at .311 with and without gas checks.
Seriously, you should use the gas checks.
GC's add bearing length that you need with the fast twist. Fit is important but it also means to the twist too.
My first experience with this was with TC, 30-30, shooting cast, scope from the bench and could hit pennies and nickels at 100 yards. I ran out of checks so left them off. Every boolit hit sideways at 50.Attachment 190552 With checks at 100, no joke.
If you don't want to use checks, use a PB but do not shorten the boolit.
Yes, I know the checks are made from metal mined in the asteroid belt but you need to "Bite the boolit." :groner:
Have some lee 312155 bullets coated and gas checked for testing tomorrow, if the rain decides to take a break. I sized these at .311 I'm not trying to shoot these faster than 1500fps.