Home Forums Hunting & Shooting AR and Tactical Rifles W-W 748 reports of super high velocity shooting 65gr Sierra GK

I used to burn a lot of W-748 back when I was shooting Prairie Dogs a few times a summer. Yes it is EXTREMELY temperature sensative. Case in point, I had worked up a load for a new Remington Model 700 VSSF .223. I was using 52gr. Speer Flat Base Hollow Points with 27.0grs. W-748. I had worked this load up in 85 degree temps. It was a MAXIMUM load but under those conditions I felt it was OK.

We got to central South Dakota a week later shooting prairie dogs and it was 107 degrees. I ended up having to keep my ammo in a cooler to be able to shoot as I was blowing holes in primers at these temps.

Upon returning home I put 10 rounds of this ammo in the freezer for a couple days. The morning I was going to shoot I placed 10 rounds on a cookie sheet and set it in the sun on the front step. After an hour I did a chronograph test. Granted this was not very scientific but I did obtain 200 FPS difference in average muzzle velocity from the cold cartridges to the hot cartridges.

I had a couple hundred rounds of this ammo loaded when I did this test and promptly pulled the bullets on all of them, dumped the powder and have not used a ball powder since, especially W-748.

I have also used the same 27.0grs. of W-748 in a 22" Ruger KM77RFP MKII .223 with 55gr. Nosler Ballistic Tips, but again determined this load was too hot for varying weather conditions. At that with the 55gr. Nosler Ballistic Tips out of the 22" Ruger my average velocity was 3154 FPS.

Given my experience with W-748 there is no way I would load that much with a 65gr. Sierra.

Larry

Had some similiar results with AA 2520 and their QC was so bad that I've avowed since the mid 90s to never purchase another AA powder if I can avoid it..

Totally SAFE loads at around 80. But we got into a match at around 100 plus some horrendous humidity, no breeze, almost killer weather in the pines of E Texas in a regional match once.... Kayla(my adopted junior shooter) shot the first few at 600 and was NAILING the center, but blowing primers so I grabbed all of her ammo, and opened my water jug with ice and water left, and dumped em all to the bottom, handed em to her one at a time as needed after wiping them off, she won the leg match that way....

I keep all my ammo in the heat, in a cooler with no ice or heat, just protects it better in the summer.

27.0 was a locally famous load for 52s here too, and got its owner Arnold Granger, in deep a few times in the heat... say isn't 748 the same as one of the surplus powders? BLC2 or some such, I can't recall...

I wonder if the 748 heat issue is the same in the 308.

Denton finds Varget to be quite insensitive to temp changes in the 308, but it shows big differences in the 223. Maybe the 223 swings more with 748 too.

Its possible. I used to think I had temp swings in the 308 but after a number of years learning to shoot half decently I deduced that it was much more my piss poor iron sight shooting skills than anything else...

I shoot five bullets currently: 275 Barnes, 300 Speer Gold Dot and just got 500 Rainer 335 HP's for plinking. Also have ran 350 XTP's and 325 Speer's. Usually whatever is on the shelf, but with the quantity of Rainers, those will be the fun, can bouncing stuff and the Barnes for letting the air out of critters, though I doubt the 335's would have a lack in that department. I am just getting the Beowulf up and running again after some self-inflicted reloading and trigger isses. I have a good load for the 335's using 35.5 grains of Lil Gun. I haven't chrono'ed these yet but believe from prior runs they should be doing about 1750-1800.

Sounds like the info in Handloader may be from AA. Those loads sound familar. Might be a bit lame to memorize loading data when you don't even intend to.

Thanks!

Seems like by memory... since all my data is boxed up for a move... that I ran around 37 of lil gun in the beowulf with Barnes 275s.. Worked grand on deer and hogs so far.

I'm sure that's close or right on the money, Jeff. I believe 37 grains of Lil Gun is max on the 335's but 35.5 puts them in one ragged hole at 50 yards using a Holosight with mine. I'll try them at 100 this weekend, but I don't shoot much with the healing shoulder these days. I shot 12 last weekend and that was enough. It's the off shoulder but they do let you know it wasn't a 223 in the rifle.

Please understand I was trying to figure how they could get that velocity with 748. I got the 52000 pressure from the link you posted and added 60000 for a maybe. I used my velocities I got with better powders and lighter bullets just to try and keep an open mind.

But I do not reccomend WW748 powder for the 223! I think they're being optomistic or simply smoking crack to think those velocities are attainable and safe. Both Benchmark and TAC give higher velocity and are less tempature sensitive, throw in cleaner burning and it's no contest.

I try to work all my loads in at least 90 degree weather. The 60 gr NBT load might be fine in colder temps but as I said it was too hot. From my limited experience, all powders are temp sensitive to some degree. Work up a safe load in the hottest temps you can and you'll be safe any other time. Even Varget will shift impact some with 70 degrees difference.

I haven't played benchmark much but in my 6mm WOA its really a great powder, though I"ve been told by Dtech that TAC might be even better.