Are you current running slug liner A with the 1 in 16" twist?If so the only thing you would gain by going .222/.223 or .224 1 in 16" twist is the ability to run different diameter bullets.Have you tried looking for heavier .217 bullets? Griffin airgun ammo has boat tail in .217 up to 44 grains (I am concerned, however, these would need more than 1 in 16" twist because of the boat tail) and Mr. Hollow point has flat base in 38 grain and 46 grain .217 according to an image search.
If I were you I would put in a TJ's .218bore .222 Grove 1:16 twist and shoot the NOE 225-39https://noebulletmolds.com/site/shop/224/225-39-fn-b2/225-39-fn-b2-3-cavity-gcMy only concern is that it is a pretty specific combination, there won't be many great opportunities for other bullets if you go that route. But that one combination should put a smile on your face
For that power I'd be very tempted to copy subsonic .22lr. Use Lyman's 225438 bullets sized down a bit and get a Redmans .22lr liner from Brownells. The 225438 is the same shape as .22 lr bullets and should be around 40 grains sized, Redman's liner is said to be same diameter as FX liners and they are very reasonably priced. Sizing system with dies you can change is available from NOE. For true .224 I would suggest bullets in 47 grain to 55 grain range (like Arsenal 225420) and 12.7" or 12" twist barrel but then you need around 90-100 fpe to make it work.
Hmm. I like this game...27" barrel, full bore ported .22" regulated at 2800 psi with around 90~ cc's of plenum will easily crack 100 fpe shooting anything between 48 and 55 gr.
500mm is quite the inhibitor, trust me I know. (both from experience and knowledge)As you said its hard to give up on the compactness that comes with shorter barrels. Add on a decent moderator to any 600/700 mm barrel and then you're well into 40"+ for most rifle.Hopefully plan A works well for you, but I think plan B is better if you already have a leshiy shooting 20 gr NSA's well
.......... My goal is at least 75FPE with an 18" .224 using 34-40gr. I'm not concerned with coming up short on power, I just need some recommendations on a barrel + projectile combination that would likely work for this configuration........
Quote from: mtnGhost on June 10, 2020, 02:38:48 AM.......... My goal is at least 75FPE with an 18" .224 using 34-40gr. I'm not concerned with coming up short on power, I just need some recommendations on a barrel + projectile combination that would likely work for this configuration........Is the 40 grains heel base from Old West Bullet Moulds an option?https://oldwestbulletmoulds.com/shop/ols/products/22-long-rifle-40-grain-heel-bullet-double-cavity-mould
You have my attention at 150bars and 72fpe. what is the plenum size and and barrel port size and barrel length combination for your set up? i might have missed that infor. oh btw, i hit 96fpe with 55grains, 80cc plenum regulated at 2800psi using 24" TJ .224 1/14 twist.