What is the heaviest weight bullet that 1-9 will stabilize?

[RBruce]

69 gr seems to work well, but what about 77 or 80?

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[imarangemaster]

Generally I have heard 77 to 80 do not work well in a 1/9. They need 1/8 or 1/7. I have heard that most 75 grain (TAP) work well in 1/9.

[JBS]

I have gotten the SMK 80 to produce sub MOA groups for me from my spacegun 1/9, however it has a 28 inch barrel and I leaned on the reloads very, very hard to get the FPS up. There was a write up on this about 12 years ago in Benchrest I think. Anyway it is not the bullet weight that actually dictates the rifling twist rate it is the length of the projectile. The reason it is commonly associated with weight is because most bullet cores are lead and the more weight in lead the longer the bullet gets.

Way back there were some fellows that worked at a Nuke Power Plant and made 223 bullets after work with J4 jackets for 69 grain lead bullets. The thing was they used Tungsten powder instead of lead. They had 90 grain bullets the same size as a 69 grain lead bullet. The things shot great even out of 1 in 12 barrels.

Down Load a copy of Greenhill formula to your PC and you can calculate what twist you will need for any bullet length.

[tdeon221]

69's are probably your safest bet for the 1/9 through a service length 20" or shorter barrel. Try the 75's you may get lucky. 1-8 up to 80 grain, 1-7 up to 80 grain and better choice for 1000 yard competition, 1-6.5 for up to 90 grain Sierra Matchking. This is in service rifles, match rifles can usually use a slower twist like JBS is talking about that works in his rifles but spinning it a little faster doesn't (usually) hurt things one bit. The small bullets 52 and below need a slower twist ideally. I've shot alot of 52 SMK's out of my service guns and they hammer in my 1-7, 1-7.7 barrels.

Tom