.243Win 55HH How Fast?

[Muddyboots]

So I have a ladder loaded up with elusive Varget. At 45.0 gr with 55BT = 4,000 fps. So what do you think? 4100? 4200?

 

[dogz]

Nosler 's end game for speed with the 55 and Varg is 3941 fps I'd say that's pretty much a good place to end up...........just a thunk

 

[Calvin45]

My grand prognostication predicts you end up going higher than 48, ending with a lightly crimped compressed load hitting 4244 fps. 244 is the bullet diameter…

 

[Muddyboots]

My grand prognostication predicts you end up going higher than 48, ending with a lightly crimped compressed load hitting 4244 fps. 244 is the bullet diameter…

You took my guess!

 

[comfisherman]

Last 15 years has taught us modern components allow for us to get away with more pressure than our pressure wives tales would indicate.

Nosler doesn't have a load that breaks 4k I think hogdon does with ramshot hunter and blc-2.

Hammer bullets are no more mythical in performance than any other 55 grain bullet, and no more than moly, boron, Teflon, etc that came before. Weight and pressure, can get more velocity one way or another but no free lunch.

The miracle is in the unknown, it's the same reason so many wildcats are so successful up until someone slaps a pressure sensor on it. 243 runs at 60k, similar more recent cartridges like 6.5 creed do 62. My guess is you can hit much higher speeds, with more pressure. We know in higher pressure rounds varget scales pretty good to the mid 60s, so 4200 at 62, or 63 is probably doable. And factoring in modern brass and primers go Un noticed with our finely tuned 100 year old pressure sign wives tales.

 

[just_jon]

I got 4150 with IMR 3031 and 4175 with W760 in my 26" 6mm Rem. I'm guessing you will get 4075.

 

[Calvin45]

Last 15 years has taught us modern components allow for us to get away with more pressure than our pressure wives tales would indicate.

Nosler doesn't have a load that breaks 4k I think hogdon does with ramshot hunter and blc-2.

Hammer bullets are no more mythical in performance than any other 55 grain bullet, and no more than moly, boron, Teflon, etc that came before. Weight and pressure, can get more velocity one way or another but no free lunch.

The miracle is in the unknown, it's the same reason so many wildcats are so successful up until someone slaps a pressure sensor on it. 243 runs at 60k, similar more recent cartridges like 6.5 creed do 62. My guess is you can hit much higher speeds, with more pressure. We know in higher pressure rounds varget scales pretty good to the mid 60s, so 4200 at 62, or 63 is probably doable. And factoring in modern brass and primers go Un noticed with our finely tuned 100 year old pressure sign wives tales.

Hodgdon has 6 loads breaking 4K.

The ram shot hunter one his 4080 at under 60kpsi.

No wishful thinking here or appealing to the unknown for free lunch.

Hammer bullets and other drive band type bullets do behave differently (I know hammers aren't technically driv bands but same difference haha…like cutting edge and gs custom had an awesome parabolic baby).

So does hbn. I know the hbn difference from my own experience. Not myth. Fact.

 

[comfisherman]

Ok. 4244 is still > 4080. It can be helped by barrel length, maybe a faster than average barrel or....

And he's using varget, that even hogdons data tops out at 4k with unknown barrel properties. 250fps might relate to the extra 3. But the hogdon lead free 55 nosler data is much slower, maybe due to lack of driving bands I dunno. All I know is 4200+ is probably possible but in the mo powda magnum variation.

 

[GLTaylor]

Muddy,
I got 4200+ with my 243AI. Load is listed in the Hammer Load data.

 

[yankee outlaw]

mmm i guess i may have to find my win model 70 in 243 and see
for my self

 

[yankee outlaw]

yep i have some nosler 55 gr and varget but i remember they did not shoot well its an older win i am thinking 1in 10 twist the sierra 85 gr bullets with imr 4350 work for me

 

[Muddyboots]

One of the characteristics I look for in maxing out Hammers is which powder achieved high velocity with less powder. The theory is the PDR does reduce pressure thus allowing more powder to get to the Hammer bullet pressure. I picked Varget for that reason cause it uses less powder to reach 4K which is extra case capacity. I love Ramshot Hunter but it requires too much powder and in fact their max load for the 55 is really a compressed load. Same with W760, H380, but Accurate 4064 looks promising based on low powder charge if Varget doesn't work out.

Muddy,
I got 4200+ with my 243AI. Load is listed in the Hammer Load data.

George, do you recall what powder?

 

[GLTaylor]

Muddy,
Win 760, F210s. Got to 4292, accuracy load was 4163. 27" barrel

 

[Calvin45]

Oh I totally understand what you're up to with the varget burn rate as well haha. My point was simply that it's certainly not even remotely wishful thinking to believe a .243 can drive a 55 to well north of 4000 without being wildly overpressure.

Bullet geometry like what hammers use (and there are others - gs custom hv drive band for example)

Progressive burn rate powders (rl26, superformance, rl 17, for examples)

Bullet coatings - and honestly mostly just HBN (moly, ws2, lubalox all have some merit but not much compared to hbn)

All these things do change the game and it's specifically in avoiding a massive initial spike upon the bullet entering the lands i beleive that allows for more total gas volume to be generated behind a projectile without exceeding a certain pressure ceiling at any point. Greater total area under the curve.

To my mind there's still room to really explore other possibilities too. Gain twists, slight choke bores, and polygonal rifling all seem worthy of experimentation.