Ridge Runner

f they would have made it in a 6.5 and not have bad pressure spikes, I'd be all over it.

If I'm gonna run that light on horsepower, I want an awesome BC in the bullet I'm shooting, you can get 6.5's approaching .7, 7mm's over .8, 270's just aren't available since wildcat bullets changed hands. even with the 169.5's and the 190 wildcats, the 270 WSM is a tad light in the shorts to make good use of them
RR

Jake Duke

This thread is old- but I'll try anyway. I have in fact made two 270 AIs. I love the caliber. It was easy to rechamber my exisiting rifle- infact they cleaned up the throat so my 26" barrel became a 25". I use the Nosler lrab w/ 62 gr of rl19 and get 3200 out of a 25" barrel. They shoot very well even with a 1-10 twist on my original barrel.

At 270AI velocity it will also stabilize the 165 matrix and the velocity is 2950 with 60 gr of h4831. Also a 1-10 barrel.

I am currently having a 270-300 win mag barrel built by PacNor. in a 1-8 28". This is for the new Berger 170's that are due this summer.

The days of the 270 being a great 3-500 yard deer gun only are over with the new offerings on the bullet landscape. I had the 270-300 win mag and not a Weatherby made because I have 500 brass for 300 win and it is a simple neck down procedure. I also had a donor 300 win mag rifle. I am looking to hit 3200+fps with the new berger 170gr .703bc hunting bullets. Not too bad for an ol' 270!

LoneWati

That sounds sweet!! How much is your new barrel going to run?

Jake Duke

Pacnor fitted, chambered and delivered a 1-8" for 585.00. I then had it nitrided for 85.00 and then cerakoted.

stalkingbear

I'm just wondering why not just go all the way down to 6.5 instead of stopping at .270 (.277)? There's already a TON of excellent bullets available. How about just choosing the 26 Nosler?

Ridge Runner

so the ole 270 as you call it will burn 50% more powder to gain 8% in MV, not very efficient, so barrel life will no doubt be short, even using ball powders your looking at a setback or barrel change at around the 600 round count.
RR

jeepkid

I'm doing one soon. It'll have a little different neck and shoulder then the standard 270-300 winny tho.

Jake Duke

Sorry i missed replying to this- the 270-300 uses 69 gr of imr 4350 a hits 3425 fps with the Cutting Edge 140gr bullet. It hits 3300 with the nosler 150s, 3250 for the matrix 165s and berger 170s. The barrel is nitrided so after 10,000 rounds ill worry about replacing it.

That is not a 50% jump in powder - and 8-10 % velocity bump when you are starting at 3,000 fps is huge! That is 240-300fps more. That is bigger than the difference between a 30-06 and a 300 win mag. So ill keep my 8%+ gains. This cartridge seems to get the most effecient velocity to powder ratio of the magnums. You can go faster with a rum case, but this is an easy conversion and donor rifles and brass are available.

Brass is one pass thru a 270-300 fl die, load and shoot.

super_hunt54

Only about 20% more powder if you take the average .270 load of IMR 4350 at 53.5-55 grains which is about the average in the books.

News Flash for you there Jake, Nitrided barrels will last a bit longer but not THAT much as you seem to think. RR is dead on correct in his assessment of around 600-800 rounds with a normal CM barrel. You can MAYBE double that assessment to 1200-1600 round count with the Nitrided barrel but that round you are talking about will be inherently hard on the throat. Just the nature of the beast.

Ridge Runner

where are you getting that data?
the 300 winny takes 73 gr of IMR 4350 to run a 150 at 3175 fps, and by the laws of ballistics a 30 cal will run the same weight bullet faster than a 7mm with the same charge due to the pressure pushing against a larger bullet base.
my 7mm stw will run a 140 at 3550 with 84 gr of H-1000, this is a chrony'd speed no way nohow will 69 gr of 4350 push a 140 at 3425 without being dangerously over pressure at 300 winny capacities.
RR