270-300 Win Mag now feasible

[CogburnR]

I have been considering re-barreling my Winchester Laredo to 270-33WM for a few years now.

They offer the 270-300WM in a .309 neck which gives me .005" neck clearance without neck-turning.

I am thinking of sending it off to Pac-Nor for them to do the whole job. Here are the specifications:

• Caliber: 270 (.277")
• Chamber: 270-300 Winchester Magnum .309 neck
• Stainless Steel
• Grade: Super-Match
• Twist: 5 groove/8" twist
• Contour: VarminterA = 1.235
  B = 0.95
  C = 0.812
  D = 2.5
  E = 5
  G = 28
• Finished Length: 28
• Crown: 11 Degree
• Finish: Polished
• Fluting: 4 flutes
• Type: Fitted and Chambered
• Cerakote Barrel Only
• H-146 Graphite Black
• Action: Model 70 CRF

Did I miss anything or is there something that might make it better??


Is the no turn neck the way to go? The do not list the neck size of the other 270-300WM choice.

 

[Big Jake Duke]

I have been considering re-barreling my Winchester Laredo to 270-33WM for a few years
Did I miss anything or is there something that might make it better??


Is the no turn neck the way to go? The do not list the neck size of the other 270-300WM choice.

Pacnor did the whole thing for me. After the barrel was indexed and headspaced, i had them unscrew it and ship the action and barrel to me iin two pieces. I then sent the barrel off to be nitrided in an effort to stop throat erosion we keep hearing about on rifles that shoot as fast as these. My local gunsmith reinstalled it and then cerakoted it.

I did not go for the larger throat and i have not had to neck turn anything, but i am on my third firing.

 

[Longtooth32]

From the 270 Berger thread...

Have you received yours yet?...

Left to right...

Berger 150, Matrix 165, Berger 170, pointed Matrix 175...all .277

 

[Big Jake Duke]

No, the grinch must have mine. Ill make a call tomorrow!

And im only 30 miles from the plant!

 

[Big Jake Duke]

Here are the limits i am finding in my rifle for an accurate effective load.

140gr Cutting Edge. 3465fps

150gr Nosler LRAB. 3390fps

165gr Matrix 3300fps

175gr Matrix. 3200fps

I dont have any 170 Bergers yet but i would expect them in the 3250 range

 

[Longtooth32]

Here are the limits i am finding in my rifle for an accurate effective load.

140gr Cutting Edge. 3465fps

150gr Nosler LRAB. 3390fps

165gr Matrix 3300fps

175gr Matrix. 3200fps

I dont have any 170 Bergers yet but i would expect them in the 3250 range

Are you able tell us what powder you used for each load?

TIA...

 

[Big Jake Duke]

I used US 869 for the bulk of the loads.

I experimented with h1000, but only a little. It was accurate- but i ran out and somethings are hard to find in the peoples republik of occupied california.

Imalso ran thru retumbo, h4831 7828.

Us869 was the best overall in most weights so far-velocity and accuracy. I am also experimenting with imr4350 in the 140s and they seem pretty impressive too.

Merry Christmas

 

[royinidaho]

I used US 869 for the bulk of the loads.

I experimented with h1000, but only a little. It was accurate- but i ran out and somethings are hard to find in the peoples republik of occupied california.

Imalso ran thru retumbo, h4831 7828.

Us869 was the best overall in most weights so far-velocity and accuracy. I am also experimenting with imr4350 in the 140s and they seem pretty impressive too.

Merry Christmas

BJD,

Load density in the 270 Allen Mag was pretty poor even with 101 grains of US 869 which was the "only" powder that could be used with 165 offerings and above. ES was gawd awful. I figured a bit smaller case would turn that caliber into a much sweeter experience.

I like what you're doing and am about to rebarrel, for the third time, with a 270 300 Win.

Merry Christmass and good shoot'n!

 

[TXAoudadKlr]

BJD,

Load density in the 270 Allen Mag was pretty poor even with 101 grains of US 869 which was the "only" powder that could be used with 165 offerings and above. ES was gawd awful. I figured a bit smaller case would turn that caliber into a much sweeter experience

Would reloader 33 not work in the 270AM with the 170berger and 175 matrix? I know it works quite well in the 7mm AM, I guess in my mind they are roughly the same so why wouldn't work.

 

[Big Jake Duke]

I will try rl33, when i can find it, but i think it is real close to us869 on the burn rate.

 

[Big Jake Duke]

BJD,

Load density in the 270 Allen Mag was pretty poor even with 101 grains of US 869 which was the "only" powder that could be used with 165 offerings and above. ES was gawd awful. I figured a bit smaller case would turn that caliber into a much sweeter experience.

I like what you're doing and am about to rebarrel, for the third time, with a 270 300 Win.

Merry Christmass and good shoot'n!

Merry Christmas,

Will you rebarrel with a 1-8 or a 1-9 twist? Will you keep it 28"?

 

[royinidaho]

Would reloader 33 not work in the 270AM with the 170berger and 175 matrix? I know it works quite well in the 7mm AM, I guess in my mind they are roughly the same so why wouldn't work.

Big kernels - powder bridging - humongous pressures.

I loaded RL-25 and RL - 50. Shot both of the RL-25 loads and hammered the bolt open, both up and out. Pulled the RL-50 loads.

With 165 and under 7828ssc worked well but is a little fast for the 165s and up.

 

[royinidaho]

Merry Christmas,

Will you rebarrel with a 1-8 or a 1-9 twist? Will you keep it 28"?

I'll stick with the 8 twist. It worked great with 130 through 195 weight bullets as long as they were Nosler BTs/NABs and Hornday BTSPs, Matrix worked well also. Monoliths, not so well.

I'll go with a Pac Nor #5 in 28" with flutes. My first barrel was a heavy fluted Lilja at 30" plus brake. Was great. Next barrel was another Lila @ 28" and lighter contour. Much nicer for hiking around mountains. Got same velocity out the 28 as I did with the 30 with exactly the same loads. I don't suppose that'll happen again.

This will most probably be my last build as I'm gonna hunt a ton more and shoot a ton less...

 

[Longtooth32]

Big kernels - powder bridging - humongous pressures.

I loaded RL-25 and RL - 50. Shot both of the RL-25 loads and hammered the bolt open, both up and out. Pulled the RL-50 loads.

With 165 and under 7828ssc worked well but is a little fast for the 165s and up.

This is why I use a RCBS powered powder measure for all my larger center fires…stick powder does not matter. The automatic powder scales are really fast now...