Printable View
I have a 28 inch McGowen with a 1/8 twist that I am shooting 140 grain Hornady BTHP at 2890 using 43.5 grains of IMR 4350. This is a max load for my rifle. I am not able to get the speeds that I see posted without excessive pressure. With my current load I am shooting in the low 4's so I am ok without any increase in speed but my question is:
I see that most are shooting H4350 and not IRM4350 is there that much advantage in the Hodgen over the IMR? Is it worth even looking into?
With only 43gr of powder you have plenty of room left in the case, so I would go to Hybrid 100V or IMR4831 or even H4831 SC or SSC, you will pick up some FPS, I would not use either 4350s with anything over 120gr bullets.
Dean
After a closer look I would even go a step further, to Win 780 or even better IMR7828.
Dean
PS: I see no reason why you should not see 3000 FPS
3000????? with a 140 grain bullet? I am down with that! I have used IMR 4831 But my groups opened way up. I went up to 45.0 grains with an average of 2941 fps but I was shooting just an inch. Im using resized 243 brass and the primer pockets are loosening up so I havent gone any higher. I did just get my hands on some Lapua brass and have another 100 on order. I think that I saw some 7828 the other day....
Ryan
RyanG, "scope" doesn't worry about loose primer pockets! He just gets out the Super Glue and keeps on packin!......;-))
Emulate at your own risk! ;-))
The sweet spot for mine is 2950 using 44 grains of H4350. Mine also liked H4831 at 44 grains and similar velocities but the H4350 gave me better extreme spreads and standard deviation. I have had mine up and over 3000 fps with both powders but didnt group as well at that velocity. Reloader 17 may be another option for you to gain more speed. Im running a 26" criterion barrel and lake city match cases.
You have the case capacity with they AI so why not use it, I have recommended some powders that you should try, but had left out what powders I would use and that would be, RL22 or RL25 and as much as you can cram in that case, lets face it a 140gr bullet is a lot to launch with that limited case capacity of 55gr, so you need to use all of it, it's not like you are loading a 264 WM with a 140gr bullet, with a capacity of 82gr where as if you use 70 or 74 or even 78gr it's a lot less noticeable and not as much loss,if you say you saw a can of 7828 I would snag it.
Dean
good info hear, just getting my stock finished up on my 260 ai so i am gonna tag in and see where this goes
Just my luck I went back and the IRM 7828 was gone. I still not sure why H4350 is the preferred powder over IMR 4350 the burn rates are so close. I am not complaining about my load however. As I stated I am shooting right at 2900 , just a hair under, and shooting high 3s to low 4s. I tried the IMR 4831 and got the speed up to where I want but my groups opened up to almost 2 MOA. Not sure if that was brass or bullet or both. Again like I said I was using resized 243 brass so I had at least 4 reloadings on it and the primer pockets were giving up. I may try the 4831 again now that I have Lapua brass.
You may have the dreaded donut going on too in that 243 brass causing some neck tension issues. Could be a combination of everything though, bullet powder and primer not wanting to get along.
I truly dont think that I am going to mess with load development anymore. I am getting right at 2900 and shooting in the 3's. Yesterday I hit a soda can at 500 yards with a cold bore shot. I may work up some more 308 brass that I have but other than that I am more than pleased with the way it shoots. Im not sure its worth the effort to try and get another 50 to 70 FPS
[QUOTE= Im not sure its worth the effort to try and get another 50 to 70 FPS[/QUOTE]
Yes it is, but that is just me, you know you will not have to do a whole new load development,just keep the same measurement off the lands and go to a slower powder until you see pressure signs, and if you haven't figured it out by they end of that pound, don't buy another one, I am sure your grouping will still be good while you are trying it out.
Dean
I'm getting 2820 out of my regular .260 with 44g of H4350 with no pressure. 24" LW-50 barrel with long throat.
Just switch bullets and go to 123 senars and you'll be past the 3000 mark with great accuracy. At a 1000 the 123's don't give up much to the 140's. I get 3000 out of a standard 260 with the 123's.
With a 28" barrel, you might try a slower burning powder. Maybe some RE22,RE25, or H1000. You should be able to get close to 3k with 140's. I'm running a 24" 8.5 twist, Kreiger. The sweet spot is 140 Berger vld, wolf primer, Nosler brass, and 43.5 H4350. This yields 2880 fps with an ES of 15 and consistent .3 moa accuracy.
I've been using 7828SSC in reg 260 rem.
Run out of room before I find pressure.
2820 out of a 26"barrel, with some more room it would be interesting.
Ryan, To answer your question of Hogdon VS. IMR The Hodgdon "extreme" powders are formulated to be stable at higher temperatures. This will yield better accuracy results over a wider temp. range. Check Hodgdons site for details.