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I fancy trying subsonic through my AI 7.62 AW with moderator. Does anyone have any load data for bullet weight and type and preferably for VV powder? What would be the maximum accurate range for subsonic?

If you want a subsonic 30cal get a 300 Blackout and use heavy boolits (247gr from NOE moulds)

dodgyrog wrote:If you want a subsonic 30cal get a 300 Blackout and use heavy boolits (247gr from NOE moulds)

Or alternatively stick with 7,62x51 and use the Lapua 200 grain B416 bullet which is the same as used in the Lapua factory subs. Powder wise I use IMR Trailboss. Effective range is 300m however they can be pushed a lot further. Start with about 12 grains and develop a load however check that rounds have left the barrel after every shot until you get a load that works for you and your AI.

ovenpaa wrote:
Or alternatively stick with 7,62x51 and use the Lapua 200 grain B416 bullet which is the same as used in the Lapua factory subs. Powder wise I use IMR Trailboss. Effective range is 300m however they can be pushed a lot further. Start with about 12 grains and develop a load however check that rounds have left the barrel after every shot until you get a load that works for you and your AI.

Thanks Dave That's the bullet sorted I'll give it a try - I don't have IMR but a good selection of VV - anything comparable there, I guess there must be as I'm sure Lapua use VV. I will see if I can pick up any IMR Trailboss. Would I need to bulk up the powder as +12 grains is very little in a 7.62 case: and standard or magnum primers? regards Colin

dodgyrog wrote:If you want a subsonic 30cal get a 300 Blackout and use heavy boolits (247gr from NOE moulds)

Thanks for the suggestion, but this is a whim with no intent of using anything other than what I already have. I have no specific need for a subsonic rifle, just wanting to see if I can make something that works.

The main point of using Trail Boss as opposed to other powders of a similar burn rate is that it is quite bulky in comparison with others. It is in little doughnut shaped kernels thus about 12-13 grains will almost fill a .308 case so no case packing is needed.

Case packing shouldn't be used in sub-sonic loads, for "normal" bullets weights (115-169 for instance) a 4.9gr load of Viht N310 will do the job nicely, it's a fast pistol powder which is positionally insensitive. Have a read of Dromias sticky on cast boolits in military calibres in the library for a lot more information.

http://www.full-bore.co.uk/viewtopic.php?f=36&t=810

Thank you all for the info. I'm just a little stuck getting Lapua B416 bullets and IMR Trail Boss!

Why is every one so hung up on rip of trail boss and jacketed bullets for subsonic loads.

Any fast pistol powder, at half the price of trail boss, and an off the shelf, god forbid, lead bullet and you have cheap easy and readily available subsonic ammunition.

Why go the difficult expensive route?

dromia wrote:Why is every one so hung up on rip of trail boss and jacketed bullets for subsonic loads.

Any fast pistol powder, at half the price of trail boss, and an off the shelf, god forbid, lead bullet and you have cheap easy and readily available subsonic ammunition.

Why go the difficult expensive route?

One could similarly ask "Why are you so hung up on cast lead bullets"?