270-300 Win Mag now feasible

[Buckammo]

I was able to shoot again yesterday evening and this morning. The disappointing thing is the inconsistency of the R-26 loads; across the board. One day they shoot the best, the next day they are **** poor. On three consecutive trips to the range now (13 shots), the load of 72.0 grs of Retumbo is averaging 0.6" at 100 yards, 59.9KPSI, 3140 fps +/- 10 fps at magazine length.

Max safe loads in my chamber (270-7mm Rem Mag.) with the 170gr. Berger at mag length:
69.0grs R-26 - 3202 fps +/- 16fps (65.4 KPSI)
70.9grs H-1000 - 3163 fps +/- 22fps (64.1 KPSI)
74.8grs Retumbo - 3341 fps +/- 8fps (64.6 KPSI)
77.1grs US869 - 3411 fps +/- 62fps (63.5 KPSI) - Compressed and erratic.

Since I broke my last strain gauge this morning by tripping over the wire, I will need to order more before I move on to some other bullets.

With the work you guys have done, I still need to play around with the seating depth some more. Good Info. Thanks,
John

 

[CogburnR]

"Max safe loads in my chamber (270-7mm Rem Mag.) with the 170gr. Berger at mag length:
69.0grs R-26 - 3202 fps +/- 16fps (65.4 KPSI)
70.9grs H-1000 - 3163 fps +/- 22fps (64.1 KPSI)
74.8grs Retumbo - 3341 fps +/- 8fps (64.6 KPSI)
77.1grs US869 - 3411 fps +/- 62fps (63.5 KPSI) "

How do you like you pressure trace?

It is on my list of equipment to get.

So, about what pressure do things like extractor marks show up typically? Is there any correlation to "pressure signs" that people use?

 

[Buckammo]

I really like it, it has been a very valuable tool over the years. There is a bit of a learning curve, and it is a pain to get the true barrel thickness where the strain gauge is mounted. Unfortunately, mine is one of the first models produced and everything is "wired". Those wires are perfect antennas for stray signals and will cause the instrument to trigger. I almost always end up with several bogus reading to sort out. The newer models don't seem to have these problems.

As far as correlation with observable "pressure signs", it really varies with the rifle and cartridge and the brass prep. With a non-belted large capacity chamber that is completely free from oil using full length sized brass....you can count on seeing brass flow in the upper 60KPSI range. Belted cases tend to hide this a little. Every modern, solid locking bolt gun that I have witnessed tend to give a sticky bolt lift starting in the low 70KPSI range. Again, these are generalizations based on a what I have seen.
Thanks,
John

 

[Buckammo]

I was able to make it out and shoot some mid range distances over the weekend. At this point in time, the 170gr. EOL will be my choice this fall for hunting the wide open fields around here. The load I have settled on is 65.8 grs of R-26 for 2960 fps. The harmonic sweet spot with this load is very forgiving and I get single digit SD's to boot. At 100 yards the load is a solid 3/4 MOA with a nice round distribution. At 300 yards (zero), the load printed three of three, 5-shot groups at just under two inches. I only fired one, 5-shot group at 700 yards and it came in at 4.75" with one called flier. At 936 yards, I fired two, 5-shot groups at less than 5.5".

This weekend we are going to a different location and hopefully I can print on paper out to 1250 yards. Thus far I have been within one click of vertical for predicted drops using the Applied Ballistics app and the multiple G7 values from the Berger website. This bullet also seems to do a bit better in the wind than what is predicted by the app or by JBM.

Has anyone else made it out lately?
Thanks,
John

 

[cape cove]

I really like it, it has been a very valuable tool over the years. There is a bit of a learning curve, and it is a pain to get the true barrel thickness where the strain gauge is mounted. Unfortunately, mine is one of the first models produced and everything is "wired". Those wires are perfect antennas for stray signals and will cause the instrument to trigger. I almost always end up with several bogus reading to sort out. The newer models don't seem to have these problems.

As far as correlation with observable "pressure signs", it really varies with the rifle and cartridge and the brass prep. With a non-belted large capacity chamber that is completely free from oil using full length sized brass....you can count on seeing brass flow in the upper 60KPSI range. Belted cases tend to hide this a little. Every modern, solid locking bolt gun that I have witnessed tend to give a sticky bolt lift starting in the low 70KPSI range. Again, these are generalizations based on a what I have seen.
Thanks,
John

Really good info. Thanks
CC

 

[Big Jake Duke]

Seems like things have slowed down here a bit, i am heading to the range this weekend to finalize my loads for this year. Competing for the honors are the Cutting Edge 140 gr at a fighting bc of .590 and 3450 fps., and the Nosler 150 LRAB BC of 625 and 3,300fps.. I will try the Berger again, but i feel it just wont be consistent enough in this configuration. It has been Psychotic and Pschoid at the same time. Love it then hate it, but we will see how it does. Bc 704. 3225 fps.

Anybody else have any reports?

Any plans for field use?

I am going to chase a Wyoming Elk and Colorado Mule Deer with mine this year.

 

[300R]

I would love to hear how the 170's are performing for everyone else and at what velocity.
I finally made the time to run in my 27 nosler and have only tried the 150 lrab,I have to say I have found them to be very accurate.I was blessed to find an accurate load on only my second test group after running in the barrel,not lightning quick but a nice low pressure load that shoots 3/4"@200m.
I should hopefully have some bergers to try in the next 2 weeks,but things take a while on this side of the world.

 

[Big Jake Duke]

What speed was the 27 Nosler? How many grains of powder and what twist rate did you barrel it at?

 

[300R]

What speed was the 27 Nosler? How many grains of powder and what twist rate did you barrel it at?

The load I settled on was 84 gr AR2225(retumbo)@3392fps,I loaded up to 85gn without any pressure but didn't pursue anymore speed as it shot so well right there.The barrel is a benchmark 9 Twist @25.5"long.

 

[270DT]

Have all my loads developed and it has been in the safe for a couple of months now. Will be using it for whitetail this fall and then off to South Africa for a springbuck hunt in April.

 

[Longtooth32]

The load I settled on was 84 gr AR2225(retumbo)@3392fps,I loaded up to 85gn without any pressure but didn't pursue anymore speed as it shot so well right there.The barrel is a benchmark 9 Twist @25.5"long.

That is smoking with a 3400fps for the 170 Berger. The most that I get is 3200fps+ with an occasional breach of 3300fps with my 270 Wby 28" Benchmark(Mark V).

I now have my Mausingfield LA in 270Wby (Benchmark 28", Sendero profile, 1-9) and I have a mag box length of 3.7" as compared to my Mark V action that has a mag box length of less than 3.4".

It has finally started to cool off here so I can go out shooting. I did not get drawn for squat. So off to shoot paper...

I have 140 rounds through the Mausingfield and cannot say anything bad about the action.

And for Big Jake...you do not need those Cutting Edge (expensive) in your competitions...Look what my 140 SSTs did at over 3600fps... I only loaded up three rounds...may have to load up some more to see if this was a fluke...

 

[300R]

That is smoking with a 3400fps for the 170 Berger. The most that I get is 3200fps+ with an occasional breach of 3300fps with my 270 Wby 28" Benchmark(Mark V).

I now have my Mausingfield LA in 270Wby (Benchmark 28", Sendero profile, 1-9) and I have a mag box length of 3.7" as compared to my Mark V action that has a mag box length of less than 3.4".

It has finally started to cool off here so I can go out shooting. I did not get drawn for squat. So off to shoot paper...

I have 140 rounds through the Mausingfield and cannot say anything bad about the action.

And for Big Jake...you do not need those Cutting Edge (expensive) in your competitions...Look what my 140 SSTs did at over 3600fps... I only loaded up three rounds...may have to load up some more to see if this was a fluke...

That speed was with the 150's,it has a bit more in though, I'm yet to try the 170 Berger but I'm thinking I'll get close to that but we will have to see where it shoots best.

 

[Longtooth32]

That speed was with the 150's,it has a bit more in though, I'm yet to try the 170 Berger but I'm thinking I'll get close to that but we will have to see where it shoots best.

My copper fouling round is a 150gr SST pushed by 77gr of H-1000 at about 3350fps...

With a 270 Nosler...I am looking forward to what you can push a .277 to....

 

[Big Jake Duke]

That 27 Nosler is awesome! 3400 with a 150 is magic. We are hitting 3300 with the same bullet and 75 grains of Retumbo to your 84 gr.

That performance will smoke the 260 Nosler.

I use Cutting Edge because they are a quality Bullet and I live in California where the idiots have made they use of lead bullets illegal for hunting. All hunting. Cutting Edge is far better than a Barnes on game performance and BCs so i practice with what i hunt with.

In Colorado and Wyoming i will use whichever load earns the hunting trip. Each fall we have a shoot off to see who gets to go into the field. That is a problem when you have more rifles you want to use than tags available!