.243 subsonic and .270 subsonic

Well just tried loads and put through crono

15grn 1784-1742-1785

14grn 1725-1720-1721

13grn 1637-1640-1630

12grn 1526-1519-1525

Think need to drop powder to about 8-9grn?
 
Well just tried loads and put through crono

15grn 1784-1742-1785

14grn 1725-1720-1721

13grn 1637-1640-1630

12grn 1526-1519-1525

Think need to drop powder to about 8-9grn?

What bullet are you using?

I'm not sure about dropping below the Trailboss recommended starting load. Maybe requires pistol powder after all to get subsonic.
 
Sorry takbok , my local Gun shop has no .270 tips heavier than 130 grn. So just doing .243 at the moment .
 
I've done a bit with subs in my 308 , couple of bits of advice

1, use a short bullet flat base round nose as they tend to stabilise better at subsonic velocitys in my experience and tbh a super slippery bullet is no advantage

2, trailboss is the way forward , I tried various powders and managed it but trailboss is easiest !

3, be aware of richochets

4, develop the load without your mod fitted and ensure you are getting no yaw by checking the target before you try with your mod on , this will save unstable bullets from fouling your baffles.

have fun !
 
With the .270 you could have trouble stabilising 150 gr bullets at subsonic velocity, with my 7mm08 Sako 75 I shoot a 160 gr cast bullet my normal load is doing 1600fps when I drop to subsonic
speed the bullets are starting to yaw at 50 metres,
I would recommend using varmint bullets Hornady make 110 gr Vmax and 110 gr HP if you are only shooting small animals they should be adequate
 
30-06 200gr cast (no gas check), 8.5gr Unique. Subsonic and 1.5" at 100m. Completely buries itself in hard oak sleepers.

Clean it with a couple of full bore shots after as moderator grows something weird from the residue of the lube otherwise.
 
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