.243 55gn ballaitic tip with n135

[Offroad Gary]

anyone using this combo?

fired 1 test through the chrono got 3633 fps with 40gn n135 67mm col 20" barrel.

poor obturation, sooty case, no pressure signs, prime not flattened.

 

info on this powder/bullet is sparce and not always consistent (web info ranges from 39gn up to 44 for max load).

 

I know I need to work up/develop myself but just wondered what anyone else is using?

 

if I adjust the burn rate in ql to match measured velocity it says the load is dangerous at 36gn, which it obviously cant be so that rules ql out for this.

 

I want absolute max velocity with this bullet, hunting accuracy will be there (rifle is a blaser)

 

 

 

[gbal]

Gary,I've played with the 243/58g-more played than serious tested,because the initial velocity(my teen dream was a Middlestead) gives way,as ever,to BC all too soon-300y ish.

Here are three commercial loadings,all 200 zero,BCs at .276,200 zero,drop /drift at 300 and 400y:

 

Win55BT@3910 fps 4.3/8.2 13.1/15.4

 

Fed 55Nos BT@3850 4.4/7.9 13.6/14.8

 

BHills55NosBT@3800 4.6/8.1 14.0/15.1

 

Looks like 100fps more really adds very little.

Of course,hot loading might 'improve' a tad,but on this evidence,hardly worth it,sssso I'd not be inclined to trade off accuracy,were there a choice.

 

Have you checked rifle twist/bulletweight-for Gyroscopic Stability-which can reduce BC-though we're still in velocity rules territory...Berger have one (based on MIller,I think)-prob ok, but worth a check.

It certainly adds to the 243's versatility.I came to just prefer the 65/68 Bench Rest bullets,perhaps because I just had them rather than a lot of 58s. Have fun-it's an easy/interesting combination.

 

gbal

[Offroad Gary]

I used to use 55's with h4895 @3950, but ive got 1.5kg of 135 going spare, i think i should be able to get something half decent. All i want to do is spin a 4" gong at 300 by holding somewhere near it them im good to go with the foxing rig.

[Offroad Gary]

43gn n 135 gives 3809 fps average (es 15), 3 shots touching at 120m. That'll do for now!