.270win Primers

[David]

Hi all, I'm pretty new to reloading and hope you all understand what I'm on about !

I have currently developed a round for my .270 as follows:
Cases - Ex. Winchester Ballistic Silver tip
Primers - Federal Lrg. Riffle
Powder - AR2217 @ 58.7 grains
Projectiles - Nosler Accubond LR 150 grain
C.O.L. - 3.360

Result - Muzzle Velocity - average 2701 fps.
Group - 0.28 MOA (3 Shot)

I tested the load and Chronographed it using 5 shots at 1 minute intervals with only a boresnake passed through between shots, I discarded the first shot as cold and the last as hot out of the string.

Shot 1 = 2693 cold cleaned barrel
Shot 2 = 2699
Shot 3 = 2704
Shot 4 = 2699
Shot 5 = 2710 extremely Hot Barrel

Now I know the accuracy is there but I was looking to grab or try to grab another 100 or so fps but I'm pretty well maxed on this load what I want to know is will Magnum Primers help achieve that goal or if you have any suggestions they would be appreciated?

The Riffle is a Tikka T3 Lite with Muzzle Brake.

[bladeracer]

Hi all, I'm pretty new to reloading and hope you all understand what I'm on about !

I have currently developed a round for my .270 as follows:
Cases - Ex. Winchester Ballistic Silver tip
Primers - Federal Lrg. Riffle
Powder - AR2217 @ 58.7 grains
Projectiles - Nosler Accubond LR 150 grain
C.O.L. - 3.360

Result - Muzzle Velocity - average 2701 fps.
Group - 0.28 MOA (3 Shot)

I tested the load and Chronographed it using 5 shots at 1 minute intervals with only a boresnake passed through between shots, I discarded the first shot as cold and the last as hot out of the string.

Shot 1 = 2693 cold cleaned barrel
Shot 2 = 2699
Shot 3 = 2704
Shot 4 = 2699
Shot 5 = 2710 extremely Hot Barrel

Now I know the accuracy is there but I was looking to grab or try to grab another 100 or so fps but I'm pretty well maxed on this load what I want to know is will Magnum Primers help achieve that goal or if you have any suggestions they would be appreciated?

The Riffle is a Tikka T3 Lite with Muzzle Brake.

By "maxed out" do you mean you are already showing pressure signs?
In which case you would want to reduce the charge to try the magnum primers and then work up until pressure signs again.
I doubt it'll give you 100fps more velocity though.
Try a lighter bullet or perhaps a different powder, or you could try coating the bullets with moly. You could try seating the bullet deeper to reduce case volume as well.

I use Remington 9-1/2M primers in all my large rifle cartridges. I tried mixing up magnum and non-magnum and didn't see huge differences in any of the calibers I tried them in so I decided to just stick with the magnums.

Why do you specifically want them to go another 100fps?
The Accubond LR has a G1 BC of 0.625.
100fps terminal velocity increase is equivalent to simply getting fifty-yards closer to your game at several hundred yards range.

[David]

By maxed out I mean the maximum recommended load for that powder and also the volume is pretty much full, certainly seating the projectiles into the powder and that is at the current overall length which is a little longer than the recommended 3.340" increasing the bullet length to 3.360 actually gave me another 44fps. in conjunction with 0.2 of a grain powder increase.
As for why I want the extra speed well its simply to reach out there a little further with a flatter trajectory some of my shots are about the 650 to 800yrd mark some times a lot less also.

Thanks for the reply Blade,

[bladeracer]

By maxed out I mean the maximum recommended load for that powder and also the volume is pretty much full, certainly seating the projectiles into the powder and that is at the current overall length which is a little longer than the recommended 3.340" increasing the bullet length to 3.360 actually gave me another 44fps. in conjunction with 0.2 of a grain powder increase.
As for why I want the extra speed well its simply to reach out there a little further with a flatter trajectory some of my shots are about the 650 to 800yrd mark some times a lot less also.

Thanks for the reply Blade,

Maximum recommended does not mean you're maxed out. Maxed out in your specific rifle could be several grains more than somebody else's rifle.
But often pushing as fast as you can might reduce the accuracy. My standard load in my .204 is 0.5gn higher than ADI's listed 29.5gn maximum but still with no pressure signs. I could go further but 30gn is full to the top of the case already.

How far off the lands is the 3.360" round?

[David]

Now I no it isn't touching the lands but as to how close it is I'm not sure, how exactly can I measure? I have tested at 59gn and there were a few to many flyers and my best group was 1.25" there was still no signs of compression.

[bladeracer]

Now I no it isn't touching the lands but as to how close it is I'm not sure, how exactly can I measure? I have tested at 59gn and there were a few to many flyers and my best group was 1.25" there was still no signs of compression.

Drop a rod down the barrel onto a closed bolt, make sure the end of the rod is flat (I use the cheap 6mm aluminium machine rod 1000mm long from Bunnings).
Put a piece of tape around the rod exactly level with the muzzle.
Flip the rifle up and drop a bullet (only a bullet, not a cartridge) into the chamber, hold it in place with your finger or a pen or something.
Put the rod back down the bore so it rests on the tip of the bullet.
Put another piece of tape around the rod at the muzzle.
The difference between the two is your maximum cartridge length with that specific type of bullet.
You will probably want to stay 20-thou (0.020") or so away from the lands.

[David]

Thank you for that info, now I've done the check and the resulting maths is 3.466" and this versus my currant O.A.L. of 3.360" gives plenty of room how ever any longer than my currant length will not fit in the Mag.

[Gamerancher]

Well that will be your maximum C.O.L then.

[Supaduke]

Unless you are prepared to forego using a mag and just top load em.


Which can be quite a pain if not at the range.

[bladeracer]

Thank you for that info, now I've done the check and the resulting maths is 3.466" and this versus my currant O.A.L. of 3.360" gives plenty of room how ever any longer than my currant length will not fit in the Mag.

Why did you decide on the 3.360" overall length?
ADI list COAL for 3.285" for the Hornady 150gn.
Have you tried shorter lengths already?

[David]

Yes I have tested shorter lengths and they were resulting in slower speeds which I don't quite understand but any way I worked up to the 3.360" which is as long as will fit in the magazine(just) and as I increased length speed increased as well.
My son uses 150gn Hornady SST and seats to an O.A.L. of 3.285" and results in a bit faster speed by about 45fps but his riffle is set up a bit different to mine and the SST's are a shorter projectile than the Nosler Accubond LRs.

[Antie]

Nosler Accubond LRs.

Those suckers are loooong.

[bladeracer]

Nosler Accubond LRs.

Those suckers are loooong.

1.390" long.
You should see Hornady's 175gn .284" ELD-X at 1.567" - that's a 7mm bullet that's 39.8mm long!