Author Topic: .260 X 129 SST's? (Read 460 times)

Propdoc03 · « **on:** December 31, 2003, 12:47:15 PM »

I am just curious as to if any of you have any data for the 129 grn Hornad SST's with H-4831SC? The latest Hornady manual I have is the 4th edition and it does not list the 260 or 4831SC and I cant seem to find it on the Hodgdon site. By cross referencing my manuals if looks as if I am right in the max ballpark? I am working with my SS Model Seven which has a 20" barrel. I have worked up to 48.0 grns of this powder which was my hottest load for today. I was hoping to acheive 2750 out of my 20" tube but am only at 2675fps. which isnt too far of my mark. I started off with 46.5 grains for the day and my groups tightened up as I aproached 48 grains to just a tiny tad over 1 MOA and my spread also tightened up to an Extream spread of 8.87fps for three shots. The primers are looking about right, I know not the best thing to read. I started off with R-19 and it was a lost cause. I still have some Varget loads to try out, but it look slike the H-4831SC might be the ticket? I had been running the 140grain Hornady Spire points with R-22 and it was working realy well, I just decided to try the lighter SST's.
PD

Graybeard · « **Reply #1 on:** December 31, 2003, 06:26:50 PM »

The new book shows max at 49.9 grains. You need to buy a new manual if you are still in the 4th. The manual shows that buys you 2900 fps in a 24" tube R700.

GB

Propdoc03 · « **Reply #2 on:** December 31, 2003, 07:03:32 PM »

Excellent, Thanks GB! I am in the process of updating my manuals and do have the new Sierra on its way with Nolser next on my list then the Hornady. I was trying to hold out until the new WSM made it into the manuals, plus I have been in kind of a non shooting mode, but that has changed! I did find some data that matched my R-19 loads and it apears that my rifle is running slow, even when accounting for the shorter tube.
I ran my numbers and with my 75fps less Vs. my 2750fps goal and it only calcs. as a .53" differece at 300yards when sighted in at 200. I even ran the number up to 2850 and still only end up with a 1.17" differenc at 300, of course the energy difference is that much less. I was using a drop tube with the 48 grains of the 4831 and it still was just about to the base of the neck and as close to compressed as it can get, perfect in my eyes! I plan on loading some more up with 48 grains to confirm that it likes that load and and will also bump it up a bit more to see what happens. For right now am pretty content with my load right now as it seemed like it was going to be very consistant in grouping and has such a low extream spread of only 8.87fps., but it can always get better, right :-)
Thanks PD

Graybeard · « **Reply #3 on:** January 01, 2004, 04:10:38 AM »

There is darn little real world difference gained by adding a few hundred fps once you approach the 3000 fps barrier. I've been playing around with the numbers trying to justify to myself building that .257 Whby. I've wanted for so many years. Just can't do it on numbers. Using the fastest and flattest 100 grain bullets in it and comparing it to my current 7-08 I'm maybe an inch or so better at 100 yards and a couple inches at 300 yards flatter with the magnum compared to the mudane 7-08. Oh well who says ya gotta need a gun to buy one.

GB

Propdoc03 · « **Reply #4 on:** January 02, 2004, 11:21:43 AM »

Just thought I would post the latest on my 260X129SST load development. I started at 46.5grns and slowly workd my was up to 49.8 grns of the H-4831SC for a max. velocity of 2810fps. I have fat fingers so dont take any of this data for granted! This is out of my 20" Model Seven. While working up it looked like 49.2grains is going to be my ticket. This load produced and average velocity of 2780fps (30fps over my goal) with an ES of only 10.45fps and an SD of 6.09. I ended up with an average group size of .72" at 100yards with the largest group be .875". This was with three, three shot groups. I did have one five shot group with this same load that opened up to 1.3" but am ignoring it. Is this considered cheating or just being honest? Actually the five shot group is not a bad looking group. This little Model Seven isnt the easiest thing to shoot off the bench or off hand as there is no weight up front and the stock is so thin., excuses-excuses :-)
Anyway now that I have a satisfactory to me load I am going to get to know the rifle better while getting some real world practice in. Now the fun begins, okay its all fun!

PD