Klem Wrote:CXR,

Be aware, H4198 is a faster burning powder than BENCHMARK - It will give you even slower velocities within max safe limits (don't use it). Check this powder equivalent chart out from the makers of the powders you are talking about. Fastest burning at the top to slowest down the bottom;
http://www.adi-powders.com.au/powder-equivalents/

For a 100-125gn bullets out of a 20" barrel the most efficient powders in a range are 8208 to 4895. I recommend 4895, and a chronograph so you know what's going on.

Plus, access an internal ballistics program like Quickload so you can do What-if's to find the best powder for a bullet, barrel length and calibre combo without having to buy it.

Mitdr774 Wrote:You really need a chronograph for checking your velocity. I know every barrel is different, but a 200+ fps difference with the same bullet and powder with just a 2" difference in barrel length seems suspect. I understand its not a bolt gun, but I just dont see that difference being that big of a contributing factor. I could be wrong though.

grayfox Wrote:

O, btw, I don't exactly trust any Lee data, maybe that's just me but you're better served by some books with Grrr expertise.

sbowhuntr Wrote:If your getting half minute moa with the benchmark why bother changing? Those are great groups but some folks are not satisfied unless they are pushing the max velocities but to each his own I guess. Im running 30.2g of benchmark with the 90g tnt which is almost max load and im getting excellent accuracy with low es & sd's. Im not one to worry to much about velocities as long as accuracy is good. I solely use my weapons for hunting and a couple hundred fps is no deal breaker because dead is dead regardless of velocities.

CXRs Wrote:I just saw this post now. My biggest reasoning for wanting the extra velocity is that I plan on using this as a hunting load, and want to minimize as much room for error as possible. I tried loading up some of the AR-comp and ended up with a mildly compressed load that shoots about 1.5 MOA, and I've loaded up a couple more bullets with that load that I have seated a bit deeper to try to see if the powder pushing out the bullets by about .005" affected accuracy that significantly. Next I plan on loading up some CFE223 and some IMR4895(when I can find some info for it, I was thing of starting at 27gr and stopping at 28.5 in .5gr increments.) I am heading to the range in a few hours to test, so I'll try to update then.

A5BLASTER Wrote:It's not wise to use 5 tenth increases in powder charge in the grendel case. The case is to small of volume for that amount of increase.

Better to use 2 or 3 tenths increases.

CXRs Wrote:Hey all, so I've been playing with my PSA 20" Grendel lately, and found a load that is giving me insane accuracy, but I dont have a chrono to check it, and I've got no idea what kind of velocity to expect.

I've been loading 27.2 grains of Benchmark behind a 123 SST, and according to Hodgdon's website and my Lee manual I should be getting around 2400fps, but factory ammo like the Black and Custom come in around 2550-2600fps. Is factory ammo that hot, or are the numbers wrong on my reloading manuals?

Valjean Wrote:It's weird, Im also getting better groups with Benchmark(1.1MOA 28.6g) over CFE223(1.3MOA 30.5g) with 123SST...then on the flip side getting better groups with CFE223 (0.4MOA 33g) over Benchmark(1.1MOA 28.5g) with 95 Vmax.

Based on general recommendations I've seen throughout the WWW, I would have thought the results were juxtaposed, but I have confirmed my findings a few times.

Valjean Wrote:I accidentally entered the wrong benchmark volume for SST123. I was using 26.8 not 28.6. It's been edited in my OP. I've been using the Hornady Reloading Manual X. Dont have a Chrono yet...hopefully for Father's Day