308 Winchester

[Rockhopper]

Firstly I'm a relative newcomer to reloading!

I have a Parker Hale T4 in 7.62/.308

I'm using PPU brass and PPU FMJBT 145 grain bullets.

I'm currently using N140 powder.

I'm struggling to find load data for a 145 grain bullet - most data is for 150 grain.

If i load for a 150 grain bullet then it shoots a bit low at 200 yards and by the time i get to 500 yards my sights are close to the 700 yard setting. I don't currently have access to a chrono but my thinking is that i need to increase the muzzle velocity somewhat to get close to a military load that the Parker Hale 5E is calibrated for (i assume??)

Any guidance would be appreciated!

[WelshShooter]

Hi Rockhopper, welcome to the world of handloading! You should be fine for following the starting load of a 150gr HPBT for the PPU 145gr FMJ.

Typically, if you cannot find a starting or maximum load for a projectile it is good practice to use the starting load of a heavier proectile. If you look at the N140 data for 150gr HPBT, 155gr HPBT and 168gr HPBT the starting loads are 40,4gr, 37,1gr and 36,2gr respectively. This shows that as projectile mass increases, the starting load decreases. As expected the maximum loads follow suit at 47,3gr; 44,2gr and 42,8gr respectively.

http://www.vihtavuori.com/en/reloading- ... ester.html

I do not know much about the rifle you are loading for, but typically on rifles with graduated sights (i.e. Lee Enfield, kar98) the sights are calibrated for a specific military loading which depends on bullet mass and velocity, as you've already picked up. Therefore, if you use a different mass or velocity then you will have to work this out by practice. For example, the load I have for my 8mm Mauser is spot on with the sights until I get out to 900m, in which case I need to ramp the rear sight up to 1,000m to get a hit. Otherwise it's a perfect match.

[bnz41]

You have a PM

+1 as Welshshooter says use loadings for 150gr bullets.

[Rockhopper]

Thanks to both of you - I now know that I'm safe and that my theories are heading in the right direction! I'll load up some five round batches and chrono them at Carlton Moor Farm and see how I get on.

Thanks again.

[Mattnall]

If you are getting good consistent results with your loading and still have enough elevation on the sights for your needs then I wouldn't worry about being at 700 on the sights to shoot 500yds.

Just enjoy what you have.

[Rockhopper]

So, would anyone like to comment on the results of my chrono session?

145 grain PPU bullets and N140 powder.

The Lee book says 42.4 grains should give me 2625 ft/sec - i was getting 2332 (average over five rounds).

43.5 gave me 2469

44 gave me 2496

44.5 gave me 2545

and 45 gave me 2500

The velocities were very consistent at 44.5 grains which makes me think thats the optimum load for my rifle however I'm still a fair way down on the 2733 that NATO 7.62x51 should give me (i don't have any to chrono sadly).

So, stick with 44.5 grains?

Any suggestions or comments would be appreciated.

[dodgyrog]

I wouldn't bother trying to emulate the Nato velocity - if you use the rounds at 2500fps why do you need the extra speed unless you are trying to reach 1000yards?

[dromia]

What were the groups like?

Theory dictates that the most consistent velocities should give the most accurate loads but this is not always true you need to shoot for groups, at least 10 rounds, to see what suits your rifle.

Ignore the Lee book they just regurgitate and plagiarise others work.

Use the Vihtavuori data for maximum and minimum parameters, that will have been pressure tested but don't expect to replicate their velocities as all guns and components are different.

As has been said don't worry about the sight settings as long as you have the elevation to get you on at the distances you want.

Top velocities rarely give the best groups.

[Alpha1]

I use the same 145 grain bullet with 43.2 of N140 it knocks down figure 11s all day at 400 yards. That's good enough for me.