.204 and Win 748

[highvel]

I have a itch to try some Win 748 in my .204 load to see if I can get similar accuracy to what I'm currently getting with Benchmark.

My question is about temperature, how sensitive is Win 748 to temp and should I really be concerned with 30-50 degree ambient variations?

Thanks

[Brian Pfleuger]

I haven't used 748 in .204 yet, but I do use it in 22-250. QuickLoad predicts the highest possible velocity in both cartridges with 748. I load it under a 35gr Nosler BT in 22-250 and get chronied speeds of 4,435fps at a load several tenths below predicted max. I stopped at that point since I like to keep pressures in the 58,000psi range. The speeds also match QuickLoad predictions at 99.97% correlation. I have noticed no difference at temperatures from about 65f up to around 90f.

The only thing I can tell you about using it in .204 is that one (trusted) TFL member told me they couldn't get above 3,900fps with the 32gr bullet without "major pressure signs". On the other hand, another (trusted) member told me that they get over 4,200fps with 28.0gr BenchMark, and I don't come remotely close to that speed at 28.0gr. It's almost like all guns are different or something?!

[A_Gamehog]

I just bought a new AR-15 upper with the 204 Ruger . I read posts on the internet and did an informal poll about "consistent accuracy loads" using certain componets

I tried,

N-140
R-10X
R-15
Varget
AA2230
Tac

Sierra 32's, 39's
Hornady 32's and 40's
Berger 35's

Hornady Brass

Fed 205 & 205M
Remington 7/2

Best light bullet, 32 grain V-max
Best heavy bullet ,39 Sierra BK
Best Powder was R-10X
Best Primer was Fed 205M
Only case used was Hornady

There is a wide load range for R-10X and the point of impact (OCW) was the same for 32's using 24.8, 25.0, 25.2, 25.4 ,25.6, 25.8 , I chose the 25.4 load

There is also a wide load range for the R-10X also and the Sierra 39's 24.2, 24.4,24.5,24.7.24.9, 25.1 25.3, 25.5 I chose the 25.2 and it was the most accurate @100 and 200 yards

Point of impact is 200 Zero for the 32's and 1" lower for the 39's. That allows me to use Kentucky windage for both loads without adjusting the scope.

I shot 450+ squirrels last week using this new gun. It was blowing so hard that my AR-15 "blew over" with the wind gusts experienced were so bad. It was on a portable table and 9" Bi-Pod with sand bag and no harm was done as I caught it before it hit the dirt. My point is for the 200 yards and less the shots fired perpendicular to the winds direction made very little difference using the 39's .

Note: Dan Newberry's OCW was the method used to create and assemble these very accurate and stable loads.

http://optimalchargeweight.embarqspace.com/

The 748 Powder is very good for accuracy in all guns tested in 223, 22-250, 34's-60's but as heat of the chamber and outside temps change so does the pressure. When it's 95+ outside you need to adjust this powder, or compensate. Very clean burning, and easy to find accurate loads.

[highvel]

Thanks guy's.
I have been using Benchmark and worked up my rifle's OCW at 25.5 gr with the 40gr. Nosler, it's a great shooter but a little geriatric in speed, average velocity is 3405 fps. I started seeing slight pressure signs at 25.7 and have done all that I can with the Benchmark.

I'm hoping that I may be able to hit the next sweet spot in velocity with the 748 and wont have to buy more powder yet, well who am I kidding, I'll be buying powder anyway.
Most all of my loads run slower than what the "?norm?" is in my VR-15, but she shoots great! Maybe I will swab the bore with some B-12 and see if it helps!
I've read quite a few posts that say the 39 gr Sierra bullets are great shooters, I plan on giving those a try.

It's all in the testing, I love the testing!