.300 PRC Satterlee Test Results

[rockchalk06]

1st time doing this test. Interesting results. Primers were kinda flat, but no cratering. No heavy bolt lift. This rifle a damn dream in half to shoot. We gotta do something about that foam over the benchrest range though. **** is in every nook and cranny of my gear lol

All shots were done @55 degrees with about a minute between shots then a 20 minute rest between shots 5 and 6. Barrel just barely warm. Rounds single loaded and chamber was open between shots and rest. No loaded round spent more than 30 seconds or so in a closed chamber. Just long enough to chamber, bolt close and a few breaths to control my shot.

Ramshot LRT was all over the place. I guess if I had to say where a node was at would be between shots 8/9/10? However the SD for all 10 shots was only 16.3

VVN570 as a bit more stable on the graph. I see two nodes. Shots 3/4/5 and 6/7/8. Yuge jump between shots 1,2 up to 3 though. Almost 30 FPS.

I can see a direct correlation on the two nodes v's what printed on paper for N570. I really like that node for shots 6/7/8. Shots 6 and 7 were 1 hole with #8 probably still making it a sub MOA group. I think I'm going to load up 10 more at 78.9 grains of N570. Shoot them all over a chronograph, 5 at 100 yards and 5 at 200 yards.

I don't know what to think about the LTR. It's a ball powder, so took up less space. N570 was "sorta" compressed. Not enough to cause a mark from my seating stem, so I know there was less dead space in the case. Both loads were COAL of 3.700" or 2.817" off the O-Give. You see some really wild shots with LRT too. Looking at the entire 10 shot string of N570, you see more consistency.

I'd appreciate any feedback.
Thanks OSA

 

[DTF370]

N570 is definitely your huckleberry in this test. It looks to be much more predictable. I found it to be a very consistent powder and it is relatively temperature stable as well. I have made it through well over 24 lbs of the stuff in two different 338 Lapua AI’s. If I have any complaints whatsoever about it, it’s just a little hard on throats. But you pay to play in this game.

I may have missed it, but which bullet are your shooting? I assume the 225 based on your numbers. At face value, I like 78.7-78.9 gr of N570. I would be curious to what your SD would be in a OCW in this range. Based on that picture I think you’ll find a wicked load with that combo. I think some honorable mentions could be H1k and Retumbo?

 

[rockchalk06]

N570 is definitely your huckleberry in this test. It looks to be much more predictable. I found it to be a very consistent powder and it is relatively temperature stable as well. I have made it through well over 24 lbs of the stuff in two different 338 Lapua AI’s. If I have any complaints whatsoever about it, it’s just a little hard on throats. But you pay to play in this game.

I may have missed it, but which bullet are your shooting? I assume the 225 based on your numbers. At face value, I like 78.7-78.9 gr of N570. I would be curious to what your SD would be in a OCW in this range. Based on that picture I think you’ll find a wicked load with that combo. I think some honorable mentions could be H1k and Retumbo?

230 A-Tip for both tests. I'm going to shoot two 5 shot groups this weekend over the Chrono. One at 100 and another at 200 or 300. Haven't decided yet.

I had a really good conversation with a load guy at Hodgdon yesterday. He spent a bunch of time with me going over all my load development so far. He really thinks I was over pressure starting at 85.7 of LRT. He uses the ADG brass in his 300 PRC and WM and doesnt notice pressure signs on the brass going past what's published. He started getting crazy numbers like I did. He recommended starting around 80 and working up. I'm going to do the 10 shot test again working up from 80 grains.

He's obviously a Hodgdon employee, but was really impressed with N570 in my test. Told me to work a little more with LRT. If you don't get what you want, bail on it and run with N570. Said to not count out H1000 either.

 

[DTF370]

Very interesting, I’m sure he has a fair amount of knowledge. H1000 burns much cooler and is easy on barrels. Very temp stable and fairly easy to find to boot. I’m not sure how it would stack velocity-wise in a PRC. In my Saum it’s the top velocity producer. Most spherical powders like LRT are sensitive. LRT is defiantly sensitive, but that may not be an issue for you. I got burned on unstable powders when I had a rifle with a somewhat tight accuracy node. I would bet you’ll find your best SD/ES with a powder with a load density of 95% or greater. I imagine that may be hard to do with a spherical powder. You may have better luck with it than I did though.

 

[rockchalk06]

Very interesting, I’m sure he has a fair amount of knowledge. H1000 burns much cooler and is easy on barrels. Very temp stable and fairly easy to find to boot. I’m not sure how it would stack velocity-wise in a PRC. In my Saum it’s the top velocity producer. Most spherical powders like LRT are sensitive. LRT is defiantly sensitive, but that may not be an issue for you. I got burned on unstable powders when I had a rifle with a somewhat tight accuracy node. I would bet you’ll find your best SD/ES with a powder with a load density of 95% or greater. I imagine that may be hard to do with a spherical powder. You may have better luck with it than I did though.

That's what the guy told me too. 95% is ideal, but I don't know if that will happen or not. Especially since I downed the charge some. I hope it does though, I only have 4.8 pounds of N570 left and 7.8 of LTR lol

 

[DTF370]

Me at Gene Sears sometime in the next 5 months.

 

[diggler1833]

My .02, which is worth .00... which is what you paid for it (other than wasting your time reading this).

I'm not a fan of the "Saterlee method" a couple of reasons (please don't get defensive just yet).

1) Seating depth plays an effect on velocity too. That includes ES and SD, not just average. Find your Saterlee node, and end up having to adjust seating depth .030 from your test...and I bet you're a solid .1 - .2gr off in charge weight to get back to that velocity. That means you're screwing with charge weights again AND who knows if your new COL is as flat in the same spot...unless you run another test.

2) Unless you can guarantee a <5 FPS SD and maybe 10 FPS ES when you shoot for groups, a sample size of (1) is a great way to get misleading results. Chances are if you're messing with a new rig, there's zero possibility you can guarantee an ES low enough to remotely validate a 10 individual shots at 10 different charge weights.

Don't get me wrong, it will give you some sort of number to go off of quickly...but it isn't high on repeatability. This is why you may see guys who favor a PRS discipline use this method, while the long range benchrest and F-class dudes avoid it.

3) I know you take a bit more care in throwing charge weights, but for the 98% of guys using the ~$500 electronic powder dispensers and scales, or just the scales in general...those frequently have an error of about .1gr every couple of throws or measures. That isn't squat for most hunting setups...but for the guy who's trying to shoot a single shot in .2gr intervals it certainly invites the possibility of one charge being .1 high, and two charges later being .1 low...thereby creating a false data point where velocity looks flatter.

*****

I will play a bit with velocity ladders if I have to switch lots of the same powder in a particular rifle, but I'll usually shoot at least 3 - if not 5 - confirmation shots to reduce error.

I'm still not a fan of 3 shot data inputs. I learned my lesson 15+ years ago when I shot a 3-shot group of .289" (I still remember the size) during load development for my 5R. I was so excited that I raced home and loaded 100 rounds of that recipe...only to discover on subsequent range visits that the load was a consistent 1 MOA load, not down near 1/4 minute. Lesson learned for life there.

*****

Now, a "Saterlee" style I'm more comfortable with is 10 shots at a waterline at distance. If you can get 3-4 of those to consecutively group close together (vertically), you might be a bit closer to that ever-elusive "node".

*****

Everyone has their own preference. As long as you end up where you want to be, I would argue that there is no harm in going whatever route.

I just hate surprises that cost me components. I remember the crappy shooting sessions a lot more vividly than I do the good ones.

 

[rockchalk06]

My .02, which is worth .00... which is what you paid for it (other than wasting your time reading this).

Now, a "Saterlee" style I'm more comfortable with is 10 shots at a waterline at distance. If you can get 3-4 of those to consecutively group close together (vertically), you might be a bit closer to that ever-elusive "node".

I have no scientific data to prove or disprove his method, I just know there have been some decent results online I've found. As you can see below, I ran this test again with lower charge weights, and got more sporadic results. If I have a node, it at shots 9 and 10, but shots 9 and 10 are no wear close on paper, Exact opposite impact. Top row left to right. Nothing is close with this powder, bullet, depth setup. I'm officially saying that my barrel does not like a 230 grain A-Tip over LRT. Shame, I have a ton of it.

So based off my previous Satterlee test of N570, I loaded up 10 rounds of N570 at 78.9 grains. Shots 6-7-8 were close.

I loaded 10 rounds and fired 5 over a chrono at 100 yards and then 5 off the chrono at 300 yards. Group measured just over an inch with an SD of 16ish. Shot #4 was that flyer that punched out the bullseye. It was almost 25 FPS faster than the other 4. I marked that piece of brass and will put it aside to use as a fouler. Aside from that, I was kind of happy with that.

Pushed out to 300, it opened up some. I took the chrono off for this test, but thinking back, I should have left it on. Wind started to pick up pretty decent with 10-12 MPH gusts, so I cannot tell you if wind played a factor in this or not.

I feel like I'm getting close. I decided to do some seating depth changes with the same powder charge of 78.9 grains. I was shooting .020" from jam with these and loaded 5 at .015" off jam, .020" off jam and .025" off jam. Anything shorter than .025" off jam, and I am getting more compression than I want. VV data calls for this load to be at 3.697 COAL and with my .025" off jam, I'm at 3.696" COAL. I don't think I've ever loaded a round longer than a .015" jump in my life. There isn't a ton of room to play with in my chamber with the 230 A-Tip.

 

[rockchalk06]

BTW @diggler1833. I do appreciate all your input sir!