270 WSM - 170 gr EOL Berger load development

Raudy707

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Mendo
I did see in earlier comments where the Weatherby was getting velocity in 3200+ range albeit is using a 28" rather long barrel. My rig is 7 lbs 15 oz with a 25" barrel and COAL is 3.012". I wanted a mountain rifle that was packable, somewhat compact and capable of hitting small targets at extended ranges. That's exactly what I got with the 270 WSM. Depending on your hunting style you can decide if the Weatherby with it's speed and nasty flat trajectory are a better fit for you. I will say that the WSM is no slouch at 3000 fps and I feel my set up is the best all around deer rifle a guy could ask for. I even use it on rugged elk hunts where I don't want to carry my long and heavy 300 win mag. A 270 wsm in this configuration with the 170 Berger at 3000 fps surpasses 95% of the rifles out there and is the ultimate deer, sheep, goat combination. Good luck in your build I'm sure you will enjoy the results with the Weatherby or WSM!
 

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Gilly509

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Feb 24, 2017
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Fairbanks Ak
I love this thread! Gave me some good insight. Im hope to get an LPA ti razor medium action for the 270 wsm and 170 gr berger. Hawkins builds bottom metal, and uses a wyatts box, spring, and follower that will handle a COAL of 3.2. I want to get a 22" HCA carbon killer 1:8 twist barrel (carbon wrapped benchmark blank). From my experience with a 22" barreled 6.5 SAUM with reloader 26. I think 3000 fps out of this barrel with reloader 26 is doable. I get 3000 fps out of my 6.5 saum with 57 grains of RL26. Based of my experience I think 3000 with a 170 berger out of a WSM case is doable with a barrel that short. I hope to build something that weighs 7.5 pounds with a scope. I will keep you all posted. Thanks for sharing your info and experience.
 

HANDLER

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i have been working up a load for my M70 270 WSM using the Berger 170gr EOL bullets and just wanted to give a quick report. We finally had a great calm day so I spent an afternoon seeing how the bullets would perform out to 2000 yards. I had previously identified an accurate load utilizing 67.2gr of Retumbo, bullet seated .015" off the lands (overall lengths 3.115"). This loads will just fit in the magazine with a little modification. The bullets are HBN coated with a muzzle velocity of 3050 fps fired through a 26" 1:8 twist barrel. As a terminal reference this load carries 1000 ft-lbs of energy at 1300 yards. I zeroed the load at 300 yards and ended up with 1.25" grouping. The Mark 4 sits atop a 30 MOA base allowing it to be dialed to 2000 yards. Using the shooter app for a starting point I identified/confirmed the following elevation adjustments: 3.1 mil @ 750 yards; 4.8 mil @ 955 yards; 7.1 mil @ 1200 yards; 19.6 mil @ 2000 yards. I confirmed these elevation adjustments with 2 consecutive hits on 18" steel plates at each of the above distances. I only took one shot at the 2000 yard plate but got the hit; didn't want to ruin a good afternoon with a miss at that point. Will need another calm afternoon to see how it will group at 1000 yards. I have yet to try the bullet on large game but it looks like the potential is there for those wanting to reach out with a .277. This turned out to be an amazingly consistent rifle/load.
What muzzle brake is that
 

VLD Pilot

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Dec 24, 2017
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i have been working up a load for my M70 270 WSM using the Berger 170gr EOL bullets and just wanted to give a quick report. We finally had a great calm day so I spent an afternoon seeing how the bullets would perform out to 2000 yards. I had previously identified an accurate load utilizing 67.2gr of Retumbo, bullet seated .015" off the lands (overall lengths 3.115"). This loads will just fit in the magazine with a little modification. The bullets are HBN coated with a muzzle velocity of 3050 fps fired through a 26" 1:8 twist barrel. As a terminal reference this load carries 1000 ft-lbs of energy at 1300 yards. I zeroed the load at 300 yards and ended up with 1.25" grouping. The Mark 4 sits atop a 30 MOA base allowing it to be dialed to 2000 yards. Using the shooter app for a starting point I identified/confirmed the following elevation adjustments: 3.1 mil @ 750 yards; 4.8 mil @ 955 yards; 7.1 mil @ 1200 yards; 19.6 mil @ 2000 yards. I confirmed these elevation adjustments with 2 consecutive hits on 18" steel plates at each of the above distances. I only took one shot at the 2000 yard plate but got the hit; didn't want to ruin a good afternoon with a miss at that point. Will need another calm afternoon to see how it will group at 1000 yards. I have yet to try the bullet on large game but it looks like the potential is there for those wanting to reach out with a .277. This turned out to be an amazingly consistent rifle/load.
Sounds like your elevation is around 6000-6200' where your shooting. 2K is a poke with a 170 grain bullet.
 

JTB

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Jul 27, 2016
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AZ
That post brings up some good memories. The 270 WSM was being fired at 3200 ft. That barrel had been retired for a year or so and I just put it back on a M70 WSM action my son-in-law had sitting around a couple of weeks ago. Loaded it with the same load but had to seat the 170 EOL about 1/8” deeper due to magazine constraints (I had modified the previous action/magazine). After sighting it in I asked my 10 y/o granddaughter if she wanted to take a few shots. This was her first time firing a magnum class rifle (with a muzzle brake). After getting it situated on the 300 yard target and taking a few dry fires she put her first two shots in a 2” bullseye so we dialed in the 1200 yard steel and she rang it (she didn’t know she was suppose to flinch). Still is a very accurate combination. I really don’t use the 2000 yard steel much since it takes too much time to check it. A month or so ago I took a couple of shots at the freshly painted 2000 yard target with my 25 CM and didn’t see any dust so figured it may have been in the rocks. Later that afternoon we drove past target and the two shots had hit the steel 3” apart. With the newer equipment and reloading components available it is not as hard as it used to be to reach out there. Mixed brass and a 4x weaver from my early years won’t get it but even my grandkids do well using sorted brass and heavies from a custom barrel looking through premium glass. Go figure
F665C200-9592-457F-9705-F39A07BD561E.jpeg
 

VLD Pilot

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It's not a matter of the bullet making the range. It's whether it makes it on target. 1500 yards vs 2000 yards may as well be another mile in wind. The 243 bullets can make the range, but when wind in present, you may never know where your bullets hit. If a guy has a 6'x6' steel plate, I think hitting steel if you know your rifle is very attainable. Just doping wind is mostly the biggest challenge.
 
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Rep 284

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Fellsmere
Came across this tread looking for some help. I have a Mark V 270Wby that I bought the 170 eol’s for and they came in yesterday so I put some dummy rounds together to get some measurements and can see a major problem with action and mag length. To get the bullet to safely eject a live round there is so much bullet in the case that will cause pressure issues. Since I’m putting a new barrel on to meet the twist requirements for the 170 (26” Brux 1:8) why not just chamber for 270WSM? Anyone running the short mag in a long action where mag and action length won’t be an issue? If so what kind of velocities are you getting?
 

Draftmule

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Oregon
R284 ~
I run a 300 wsm in long action and is very forgiving for long bullets. But prior to ditching the fine 270 Wby try the new 165 Nosler ABLR or depending on your barrel the regular .277 150 grain Accubond which is also very new. Great question on the 270 Wsm + longer action! Will look forward to members input that route.
 

VLD Pilot

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Northern, Mi
Came across this tread looking for some help. I have a Mark V 270Wby that I bought the 170 eol’s for and they came in yesterday so I put some dummy rounds together to get some measurements and can see a major problem with action and mag length. To get the bullet to safely eject a live round there is so much bullet in the case that will cause pressure issues. Since I’m putting a new barrel on to meet the twist requirements for the 170 (26” Brux 1:8) why not just chamber for 270WSM? Anyone running the short mag in a long action where mag and action length won’t be an issue? If so what kind of velocities are you getting?
You'll be at around 3.130 running the 170 Berger's. Too long for a SA. Velocity will be very close to 3100 fps. That 3.130 measurement is in the lands. Depending on how far off them you are, you'll still need a LA to run them without losing case capacity. You could use the Weatherby action for the 270 WSM and be perfectly fine.
 

Rep 284

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R284 ~
I run a 300 wsm in long action and is very forgiving for long bullets. But prior to ditching the fine 270 Wby try the new 165 Nosler ABLR or depending on your barrel the regular .277 150 grain Accubond which is also very new. Great question on the 270 Wsm + longer action! Will look forward to members input that route.
I’d love the keep it a Weatherby but don’t think it will be very efficient with that much bullet in the case. The 270 WSM fixes that problem with plenty of room to set the bullet out. I’m wanting the 170 to extend the range to beyond 1000 yds. Can’t find load data on the 170 in the WSM, guess I’ll have to call Berger on Monday. The ABLR is good bullet but I already have 200 170’s to go through. Just trying to figure this out so I can order the reamer. But I won’t be getting rid of the original barrel so I can go back to the 270 bee😊
 

Rep 284

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Fellsmere
You'll be at around 3.130 running the 170 Berger's. Too long for a SA. Velocity will be very close to 3100 fps. That 3.130 measurement is in the lands. Depending on how far off them you are, you'll still need a LA to run them without losing case capacity. You could use the Weatherby action for the 270 WSM and be perfectly fine.
3,100 would make me a happy camper👍🏻
 

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