No love for Win 748?

[Lemonaid]

I'm having good results with Winchester 748, both in accuracy and velocity consistency.
Published load data has it on the upper end for velocity for a number of bullet weights.
So, what's not to love? or Why isn't it more popular?

[kmon]

older powder but a good one, think more gravitate to the newer stuff much of the time. I have burned a lot of it in the 350 Remington Magnum over the years and some day might burn more in the Grendel. Good to hear you are getting good results with it as I still have about a half pound I need to shoot in something, might just give it a try in the Grr

[A5BLASTER]

I'm having good results with Winchester 748, both in accuracy and velocity consistency.
Published load data has it on the upper end for velocity for a number of bullet weights.
So, what's not to love? or Why isn't it more popular?

So what is your load? And what did the pressure ladder look like?

[Jimla]

People use newer powders because they often are less temperature sensitive or have additives that lower copper build up like CFE223. Many new powders are designed for AR gas systems.

[Lemonaid]

So what is your load? And what did the pressure ladder look like?

These are my notes/records. I had to do a bit of educated guess work for the 130 Sierra Game Changers.

Winchester 788 Results
All, Hornady brass, cci 450, 24 inch BCA barrel

Sierra 130 GC, Win 748 Max 28.6 Max vel = 2338 (data from 140 speer hot core) 2.280“ oal

26.0 = 2232, 2247, 2243, 2238, 2220 1.840“ group ave 2235 sd 10.55
26.5 = 2281, 2271, 2291, 2286, 2264 1.435“ group ave 2278 sd 11.01
27.0 = 2318, 2319, 2308, 2333, 2325 1.105“ group ave 2320 sd 9.23
27.3 = 2339, 2346, 2334, 2345, 2336 2.585“ group ave 2340 sd 5.33
27.5 = 2363, 2366, 2351, 2360, 2369 2.755“ group ave 2361 sd 6.90
27.8 = 2387, 2398, 2381, 2386, 2398 2.840“ group ave 2390 sd 7.64 Mild to med swipe

Speer 90 tnt, win 748 max 33.2, max vel = 2899, 2.192“ oal

32.0 = 2811, 2820, 2809 (2 error of 3815 and 3682) 2.612“ group ave 2813 sd 5.85
32.5 = 2844, 2842, 2851, 2846, 2835 5=1.930“ 4=.945“ ave 2843 sd 5.23
32.8 = 2882, 2859, 2855, 2880, 2918 * Good accuracy! .620“ group *Retest!* ave 2878 sd 25.0

Sierra 107 MK, win 748 max = 28.0 (estimate max= 30.0) max vel 2600

27.0 = 2400, 2390, 2401, 2387, 2381 2.550“ group ave 2391 sd 8.58
27.5 = 2444, 2459, 2442, 2467, 2434 3.335“ group ave 2449 sd 13.44
28.0 = 2455, 2465, 2460, 2441, 2441 3.370“ group ave 2452 sd 10.99 *swipe med. to heavy

So far my gun just absolutely hates the Sierra 107 MK. no matter what powder or seating depth.

[meatsweats]

I?m having a hell of a time with the Sierra 107 TMK as well. I?ve tried TAC and Benchmark at multiple OAL?s. The only thing I haven?t tried is switching up primers (CCI 450?s).

Your SD numbers look good. NICE!
MS

[VASCAR2]

I’ve used Winchester 748 then it disappeared off the shelves for several years. I bought several pounds of CFE223 and have been working my way through what powders I have in stock. I’ve shot a lot of 5.56/223 with W-748, it’s good powder for several cartridges.

[Djgrendel]

I've burned a few lbs of 748. It works pretty good. I use it mostly for my summer time varmint loads. I'll see if I can find a link, but I do remember a friend of mine sending me an article that talked about 748 about 5 or 12 years ago. The article stated that 748 was similar to cfe in the fact it would help with barrel fouling.

[Kswhitetails]

While on that subject, has anyone had any issues with copper fouling in their Grendel?

May start a new thread on the topic, but I've not noticed any detrimental levels yet. Several thousand rounds, a simple patch and CLP every two hundred or so, and never had any accuracy issues which is when I usually go after copper fouling first.

On a similar note, I'm seeing similar low wear sign in by muzzle and throat. Grendel seems thus far to resist copper fouling and throat erosion. Probably due to the low chamber pressure and temperature.

[Djgrendel]

I have not noticed any real copper buildup. I don't clean my barrels to be squeaky clean very often. Only time I really do, is when changing bullets and accuracy testing Especially if going from jacketed to mono or vice versa. I did look at the MSDS for win 748. It does contain tin that is used as copper oxidizer.

[Lemonaid]

I?m having a hell of a time with the Sierra 107 TMK as well. I?ve tried TAC and Benchmark at multiple OAL?s. The only thing I haven?t tried is switching up primers (CCI 450?s).

Your SD numbers look good. NICE!
MS

The SD numbers were what caught my attention, Win 748 has the best overall SD numbers out of all the powders I've tried for the Grendel so far. (H332, CFE 223, 8208 XBR, 2200, 2230-c, power pro varmint).
Right now my favorite powder is a battle between Win 748 and Power Pro Varmint.

[Lemonaid]

While on that subject, has anyone had any issues with copper fouling in their Grendel?

May start a new thread on the topic, but I've not noticed any detrimental levels yet. Several thousand rounds, a simple patch and CLP every two hundred or so, and never had any accuracy issues which is when I usually go after copper fouling first.

On a similar note, I'm seeing similar low wear sign in by muzzle and throat. Grendel seems thus far to resist copper fouling and throat erosion. Probably due to the low chamber pressure and temperature.

Exactly! I was wondering why I wasn't seeing any copper fouling as well. Please start a new copper fouling thread to get more data!

[ike838]

Do heavier bullets require a reduced load of any given powder? Looking at the data above it would seem so but I'm not a reloader and was wondering if that is true in general.
Am I wrong to assume that a heavier projectile will increase chamber pressure ?

[Lemonaid]

Do heavier bullets require a reduced load of any given powder? Looking at the data above it would seem so but I'm not a reloader and was wondering if that is true in general.
Am I wrong to assume that a heavier projectile will increase chamber pressure ?

You are correct. More details on the process available in most reloading manuals. (use the forum search with "pressure curve")
An example for interesting reading:

http://www.65grendel.com/forum/showthread.php?16709-Slow-Barrels-and-Chamber-Pressure&highlight=pressure+curve

[LR1955]

Do heavier bullets require a reduced load of any given powder? Looking at the data above it would seem so but I'm not a reloader and was wondering if that is true in general.
Am I wrong to assume that a heavier projectile will increase chamber pressure ?

ike:

The answer is that it depends on the burning rate and bulk density of the powder. That's why guys use powders designed for the bullet they want to shoot. If you use a powder too slow for the bullet, you can probably pack as much of it into the case as possible and not get velocity or pressure. If you use a powder too fast for the bullet, you are in dangerous terriroty.

Bottom line is to use published load data and you will be fine. If you want to learn more about it, let me suggest you run some searches on web sites of powder companies. They normally have information about powders in general in their first chapter.

LR55