I downloaded the text file in the reloading data thread but I'm not seeing my particular combo of components.  I was wondering if anyone could share some load data with me.

Bullets are M193 pulls (55 gr FMJBT w/ cannelure)
Powder is Win 748
Primer is Federal SRP #205
Brass is mixed

I'm seeing data all over the place for Win 748 but it sounds like 26.0 gr is at least a safe starting point.  Does that sound sane?  I'm looking for spec 3165 FPS out of my loads.

My Lee book lists start as 23.1 with WIN 748.  Max is listed at 26.3, I definitely wouldn't start at 26.

Says the max load will get you 3150 fps.

Wow....the numbers for this stuff are all over the place.  If you look HERE you'll see several recipes listing 26 grains with a 55 gr bullet.  

ETA:  but I do also see that they're getting velocities around 3050 with longer barrels.  Wonder if I should be looking at a different powder, or my expectations for velocity are too high.

Link is broken for me.

Winchester's website lists 22.5gr as starting load with 55gr. Barnes TSX.

I'd start around 23gr.

Yeah, that sounds like a good plan, I think I'll do that.

26.3gr is Max for 55gr SP according to Hodgdon.

http://data.hodgdon.com/cartridge_load.asp

Be careful with barrel length data.  Some folks give 16" bbl results.  Hodgdon's muzzle velocity is all 24" bbl for their rifle data unless specifically noted otherwise.

Also, be careful that you are not looking at some other weird bullet that is not the FMJBT configuration.  I see some listings showing COAL at 2.26 with 55gr bullet.  That has to be some kind of weird bullet not to fall out of the case neck at that COAL, certainly not a LC 55gr FMJBT.

Looks like 26.2gr is listed as max by most folks.

Your muzzle velocity is going to probably be under 3,000 fps for a 16" carbine.

I use W748 and get 3200fps out of a 20" using 25.5grs.
24.5 gets 3k, so if they are just plinking loads, I would back down to save the brass.

I once had someone give me a couple 8# cans of W748 that I used for prairie dog loads using 55 V-Max's. In cold weather 26 grains was OK, but in hot South Dakota in June, I had some very flat primers. I wound up using 25 grains and everything was fine. W748 is temperature sensitive. Be careful with it in warm weather.

25 of this is similar to the standard 25 h335 load.

I played around with w 748 all summer long using Nosler 50 gain BTs, 52 grain match, 55 grain Varmageddon, and Hornady 55 grain FMJBT. In the summer heat, I was running 27.1 to 27.5 on the 50/52s and 26.6 to 27 on the 55s. This was with R-P and FC brass with #41 primers. The only problems with excessively flattened primers were encountered with the 55 grain Varmageddon due to the flat base. I could get at a minimum 12 reloads with annealing every other reload.  The 50 grain BTs shot a no shit 1.5 inch 5 shot group at 300 yards. At 100, my eight year old daughter could shoot 5 shot 1/2 inch groups.

Just yesterday, I loaded up some of the 52 grain match with 28.5 and 29 grains. Even with the cooler weather, there were flat primers, but no ejected primers. They chronographed at 3350 and 3410, respectively. This is out of a 24 inch barrel. Not a chance I would try that in August. The brass really took a beating.

Compared to other powders that I have used, 748 seems to be pretty mellow. H322 or the old 8208 surplus burns way quicker, while the 748 is kind of like whoosh, like idling down the freeway. Nothing too scary about it.

Also, pay attention to the bearing surface of the bullets you are using. This affects pressures big time. Chamber dimensions affect it also. I am using 5.56 chambers.

My standard P-dog load used to be 28.5gr. 748 and a 52gr Sierra HPBT at 3,450FPS (24").  Shot great!   Never had any pressure problems.  Lyman's old pressure tested data ran to 30.0gr max.  Of course I worked up in my guns and it was safe.  Do the same!

Was this speed in the summer?

Yes about 80 degrees.  I have not had a problem with heat P-dogging although it gets dang hot!  I try and keep the ammo can in the shade.

Ok, I have my base loads worked up.  I created 5 rounds of each powder weight going up .5gr starting at 23gr up to 25gr.  I shoot primarily 3 gun, so I'm looking for "on paper" or "on steel" out to probably max 200 yards for 95% of what I do.

I'll hopefully get these across the chrono this week.  I'll let y'all know where they come in at each powder weight out of a 16" 1:9 barrel.  

Thanks for your help guys.

Best accuracy load using 748 and 55 fmj bullets in different AR's has been with 25.9-26.4 grains. My experience with 748 is that to get 3100 fps plus in a 20' barrel you're going to have to push the limits and in hot summer temps you can easily run into pressure signs. I wouldn't go higher than 26.4 with velocity around 3000 fps. I've shot a lot of .223 Win 748 loads but have switched to H335 with 55 grain bullets. Hodgdon's load recommendations got higher velocity without pressure problems than using 748 in my loading.  Interested to see your chrono results.

Thanks rg.  I've done a fair bit of reading on various forums and I'm seeing a common theme, which is that 748 is not a great powder for .223.  If my understanding of the physics is correct, I'm not safely going to get 3100 FPS out of this powder through a 16" barrel.  I'm not too concerned about a specific velocity except that I want to create a load that jives with a standard .223 bullet drop compensator reticle (once I get one).

On the contrary, I think 748 is a wonderful powder for the .223. I have the Mark AR scope with the elevation knob set for the 55 grain bullet with 1, 2, 3, 4, and 5 on the dial for up to 500 yards. What it does really is it gets you in the ballpark. For instance, a 50 grain Nosler Ballistic Tip loaded with 27.5 grains of 748 is dead on at 100, for dead on at 200 set it at 2 and one click, for 300 set it at 3 and three clicks. I could flatten that out with a bit more powder I suppose. That coyote I drilled with a headshot at 250-300 yards didn't know that I wasn't dialed in dead nuts. If you develop a load and shoot it, you can keep notes on how much dial up you need.

26 is probably fine but its too high to start with. Also, remember this is reloads, not new components. Trying to push them to the max to match mil loads, which also happen to be one of the cheapest boxed rounds you can buy new, is not always a good idea. I usually buy my m193 or m855 and reload plinking or accuracy loads.....