Changing Vit N160 to N140 with 80gr Barnes TTSX in .243

[Hugh HM]

I have been using, with great success, 40.5 grains of N160 with 80gr Barnes TTSX in a 20" .243 on Roe for over 5 years. I have been told that the N160 is a bit slow for the 20" but it has worked well so I haven't changed it. I have finished the tub and have been unable to get more so have switched to 38gr of N140. This N140 load is very accurate (so no complaints there) but I am getting severe meat damage. Fist size exit wounds and large angle deflections (45 degree +) as the round passes through the deer which is a touch alarming. Can anyone provide any insight? Do I need to back this load off and reduce velocity? I am not getting any excessive pressure signs.

Many thanks for any sage advice.

 

[Ginc]

I run 80gr TTSX even hotter—42gr of N550. I haven't noticed excessive damage; large deflections occur when the bullet loses speed after hitting heavy bone.

 

[Jagged77]

Your N160 charge weight is on the low side so MV will be down - plus the short barrel. Maybe as low as 2800 fps. The N140 at 38gr is at the upper end of max load data and might be producing higher MV’s of around 3100 fps. Just one thing to watch if you reduce loads is that the case capacity will be under utilised.

 

[Bowland blades]

I have been using, with great success, 40.5 grains of N160 with 80gr Barnes TTSX in a 20" .243 on Roe for over 5 years. I have been told that the N160 is a bit slow for the 20" but it has worked well so I haven't changed it. I have finished the tub and have been unable to get more so have switched to 38gr of N140. This N140 load is very accurate (so no complaints there) but I am getting severe meat damage. Fist size exit wounds and large angle deflections (45 degree +) as the round passes through the deer which is a touch alarming. Can anyone provide any insight? Do I need to back this load off and reduce velocity? I am not getting any excessive pressure signs.

Many thanks for any sage advice.

If it works carry on with N160 . I ran a 243win for decades using nothing but N160 although that barrels life with a whole range of bullets. Deflections are more likely not stabilised, or the bullet is over expanding ( the 243 will really be sending them fast ). Meat damage in a 243 can be mitigated by a heavier / tougher bullet 95 -100 is perfect and the N160 is the powder
see what occurs if you drop back the charge in the 80 grain copper but your real issue might just be the TTSX is just a tad too slow a twist in your 243