Interesting results with new 270...

[idahohunter8]

So I have been playing with another 270 (cant have too many) This one is a Tikka t3x Superlight (22.5" fluted barrel) That is bedded in a McMillan Sako Classic Stock with Talleys and a Swaro Z3 4-12X50 BT on it - Barrel is fully floated and I adjusted the trigger down to 2.5 pounds...Great little 7.6 pound package...

I headed out today with the following loads: 58, 58.5, 59 of H4831sc and 140 AccuBond , CCI 250, loaded to 3.345 (magazine is 3.350) I was thinking I would be pushing pressures at 59...Well 3 shots at 59 grains later I had a 1" group, BUT - Velocity average was only 2890 (high of 2909) and case showed no real signs of pressure - Primers rounded, no markings on the brass, nothing to suggest anything over pressure limits.

This had me curious so I raced home and got a few 130 partiton rounds that are loaded with 59.0 of H4831. In another 270 I have with a 24" barrel, this load is max but also gives me 3100 FPS, SO I wanted to see how pressure and velocity of these proven rounds would go in the Tikka.

I shoot 6 rounds - 2 3shot groups - both under 1" but again velocity was down - 2985 average BUT no pressure signs at all. Do you think that the tikka may have a little "looser" chamber from the factory thus allowing less pressures? Thoughts? I am pretty sure the chrono is on as I shot early in the morning with overcast - there was very little to no direct sun on it during any of the shooting. Chrono was 12' from muzzle approx.

My goal for this rifle was an accurate 140 AccuBond at around 3k. I am going to load and test 59.5, 60, and 60.5 and see where that gets me, but considering there was no signs of over pressure at 59, I am thinking I may be able to get to 60-61 grains safely.

 

[Thebear_78]

All the tikka rifles have a longer tapered throat, I have never found one that didn't need more powder to achieve the same velocities some of my other rifles would.

It's a pretty common complaint but not a big issue if you reload, just add a touch more powder to get where you ant to be.


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[mjcmichigan]

1+ on longer throat


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[1Shot]

Also take into account that no two rifles are exactly alike. I started loading for a 270 Win around 35 years ago and back then the manuals and latter when Hodgdon started putting their powder in plastic bottles the max load listed right on the bottle was 60 grs H4831 with 130s. In a number of Remington rifles over the years that has been the most accurate load for me. Always well under MOA and velocity between 3100 and 3200 fps and has never showed any pressure in any rifle. I was shooting mostly Sierra Game Kings and Nosler BTs. Deer killers they are, BANG FLOP. Good luck and have fun.

 

[Guy Miner]

Well, you are comparing two different rifles, with different chambers and a 22.5" barrel vs a 24" barrel...

And 2900 fps with a 140 isn't exactly slow! I doubt the buck will study the ballistic charts closely enough to evade being tagged...

Work up the load you're happy with. Time to time I've gone beyond "book" maximums, but gently, carefully.

Seems your Tikka is a really nice, modest weight hunting rifle that should bring great results afield!

Guy

 

[Gunner46]

^ That.

 

[idahohunter8]

So I got back out this morning before work. I took out 10 rounds - 5 140 accubonds with 60.0 of H4831sc and 5 at 60.5. I shot 60.0 grains and sure enough, just started to hit pressures. No marks on the brass, but primers just started flattening out. Accuracy was great - 5 shots at approx 1.25" and velocity average was 2960. I knew these loads were as high as I probably should be going. I did shoot the 60.5 grain loads and that half a grain was too hot, marks on the brass and flat primers - average velocity was approx 25 FPS faster.

So this testing has lead to a couple conclusions:
1. Tikka may have a longer throat/looser chamber that allows for an extra 1-2 grains powder before maxing.
2. 140 AccuBond at 2950 will be the load for this rifle.
3. This rifle may just have a little slower barrel, however at 2950 that should translate to around 3k with a standard 24" barrel.

 

[Guy Miner]

I do believe that the new load and rifle will be mule deer approved!

Or, whatever you choose to hunt with it.

Guy

 

[6mm Remington]

Guy gave great advise. I load for a buddy who has a .270 MTN rifle with the 22" barrel. His load is 59 grs. of H4831SC using Federal Magnum primers. His bullet though is the 130 gr. Partition &/or AccuBond. His load if I recall correctly is right at 3000 fps. As many have stated lots of variations between chambers and barrels. What you were getting fps wise is about right I believe. H4831SC seems to be a great powder for the .270!! Best of luck.