.243 muzzle velocity

[MJR]

I wonder if anyone can give me some advice. I run a Tikka 595 action .243 with an 8 twist 24" border barrel. It was chambered with a ptg reamer to allow 105gn bullets to be seated with the boat tail just in front of the shoulder/neck junction. The gun is a solid 1/2 moa performer but I just don't get the muzzle velocity I see some of you guys are getting. My load is Lapua brass, cci BR2 primers with 41gn H4350 and 105gn Amax. MV measured with a magneto speed is averaging 2925fps. I've got 1038 rounds down the barrel so far. How are you guys getting to 3100 fps?
Thanks.

 

[jonbearman]

Are you measuring for pressure signs about .200 thou from the base? The reason I ask if it isn't showing pressure signs like flattened primers you could up the charge in 2 tenth increments till pressure rears its ugly head. Once you reach the higher pressure and the primers are just flattening you back off a couple tenths to avoid pressure concerns later. When it gets hot out you may have to drop another couple tenths for 85-95 degree days. There are other powders to try also. It isn't cast in stone that h4350 is always the best powder in your rifle with the bullet you chose. What powders do you have? When I shot 100 grain bullets I always used h4831.

 

[MJR]

Jon, thanks. I tried H4831 and 4831sc. Accuracy was good but a bit slower. I found the max load of H4350 at 41.4gns, slightly sticky bolt lift and very faint ejector swipe on the base of the case but I didn't measure the case. I full length resize to bump the shoulder 2 thou with Forster dies.

 

[jonbearman]

It looks like you should start looking at slower powders. WW780 comes to mind with heavy bullets. How much neck tension are you using? How about H1000? I know AA3100 is also pretty good with heavys but after I write this,someone will say he gets 3300FPS with varget,LOL

 

[MrMajestic]

24" tube isn't helping your cause. I think you are using the correct powder and with that accuracy I would learn my dopes and live with it. JMHO

 

[half]

I quit H4350 and went to N165 in my .243wssm. I got pressure really early with 4350, around 2950fps. I run about 3100 with 165. I am using 105's and a 26.5 barrel. How this helps.

 

[MJR]

Thanks guys, I have no 165 but I will try some in the future.

 

[bheadboy]

if you can not find 165 try RL22 as it is in the same burn rate range
BOb

 

[Changeling]

You're still running a 24 inch barrel, I doubt slower powders will help much if any.

 

[MrMajestic]

I said I would stick with H4350 however if your "need for speed" overcomes you, it happens to the best of us, try Reloader 17 and VhitaVuori N550.

 

[mmcu]

With your setup, you're seeing the velocities you should expect with a 24" barrel. If you really want to push velocity over accuracy, RL-22 MAY help.

 

[sbhooper]

It looks like you are right where you want to be. That extra 100 fps is not going to do anything but cause more wear on your rifle. I chased velocity maxes in my 7mags for years until I figured out that all it does is wear your barrel out faster.

If you want to get to 3100 fps, then get a 6mm Remington or such. The .243 will perform very well with 100-grain bullets at 2900-3000 fps. Hornady Interlocks perform perfectly at that speed.