I have been considering purchasing a 6.5 RPM Backcountry TI for some upcoming mountain hunts but would prefer something with a little heavier bullet choice; would be hunting anything from sheep to moose.  It seems that Weatherby has cracked the nut of keeping the action light weight by going with a standard bolt in a standard action instead of a magnum bolt in a short magnum action, and a proprietary case that has magnum capacity.  .280 AI has about 68 grains of H20 capacity while the new RPM case has 81 grains; similar to the WSM series.  It seems to me the case begs to be necked up to 7mm and .308 in the same action.  Any rumors floating a round out there that Weatherby may be doing just that for 2020??  7mm RPM, .300 RPM?  Inquiring minds want to know.......

Sounds like you know what you are doing, I also just bed the tang of the actions and clearance the sides. I make sure the magazine box is free floating. My new 340 weather mark still has the pressure point and like you will leave it unless the accuracy goes south.

.    That’s basically it, bed the rear tang and the recoil lug area, relieve the sides of the lug and the action screws and you are usually good to go depending on the action type; and always make sure the magazine box floats and not binding; Prep is the key.  Some of the bench rest guys do a complete “Glue In” bedding job with no relief.  The Mark V I just got didn’t have any relief anywhere; a very tight fit but it shoots which shows nothing is etched in stone.  Bedding compounds have changed throughout the years as well...today I use Aluminum Devcon. 

I free floated my ultra light 6.5-300 and bedded the first 3 inches of the barrel and it shoots 3/4 inch groups with 140g accubonds going 3400fps. Shot a 1.25 inch group at 350 yards. I have done this with 3 ultralights and they all shot better and more consistant.

I was very skeptical of this rifle when I first got it and found out it had a pressure point.  Many years ago I worked in a custom gun shop and bedded more rifles than I could possibly remember.  Over the years we consistently found that free floated barrels were more consistent and rarely could get a rifle with a pressure point to shoot consistent groups. We never put pressure points in our own custom rifles and I sanded and Dremeled out many that had factory pressure points when we glass bedded for our customers.  On heavier bench rest guns we completely free floated the barrels and most hunting rifles as well.  On some light weight hunting rigs we would bed the chamber area with good results.  But the way this 6.5-300 shoots I think I will be leaving it in for now unless I see accuracy consistency go south when I shoot it a bit more.  “If it ain’t broke don’t fix it”.  The .257 Weatherby that I showed groups for was a Remington 700 CDL with a pressure point and I restocked it with a McMillan.  I glass bedded only the action and it’s shooting great. Doing more load testing today.

+1 on the 100 ttsx in a 257 Roy, my S1 loves them while my S2 likes the 110 Accubonds.

    I did try the rest of the .257 Weatherby factory loads except for the 120 gr Nosler Partition. The 100gr Norma Spitzer, at 3415 FPS, gave the best accuracy but was lacking a little on velocity. The 100 Barnes TSX, at 3448 FPS had acceptable SubMOA accuracy but also seemed to lack velocity for this cartridge, but would certainly more than do the job on deer sized game  The 110 Accubond while delivering more velocity than the 100 gr loads at 3510 FPS lacked the accuracy I was looking for.  I’ll have to try the 120gr partitions some day.

Well, I bought the ULW Mark V in 6.5-300 Weatherby and I am extremely happy with the results.  I think I have found my ultimate Western Mountain Rifle. I threw a VX3i in 4.5-14 on it just to get started and my leave it on.  I was going to put a VX5HD on it but trying to keep the weight down and that scope is very limited in adjustment for eye relief due to the short tube length for the front ring.  I tried the 127gr Barnes LRX ammo and got a .430” group at 3459 FPS and SD of 18 and the 140gr Swift A-Frame gave me a group of 1.25” at 3376 FPS and SD of 24.  It took 3 shots to get the gun zeroed so at this point the rifle has 9 rounds down the bore and load work is done.  I don’t even think I’ll attempt to handload for this rifle which will be a first. Just need to make a final decision on the scope and then do a final sight in with the 127gr Barnes.

The loads that I have are not exactly practical. They shoot really good but I don’t know if a 129 grain SST striking a Whitetail will be devastating or disastrous when it’s leaving the barrel at over 3600 fps?
I want to mess with some Speer 140 grain GoldDot bullets. They are pretty cheap.

I would think that would depend on your available shots.  In my home area I use a 6mm-06 (basically a 240 Weatherby) with 87gr Hornady SP’s at about 3750 FPS and have shot many white tails.  I have plenty of time and only shoot broad side rib shots.  The bullets never exit and the deer drop like they have been electrocuted never taking a step. I just picked up a new Remington 700 in 257 Weatherby and I want to try that as my new Whitetail rifle with 100gr Nosler BT’s.  I learned many years ago that “Speed Kills” quickly( with light to medium weight bullets) especially in game up to Caribou size.  In elk and up I go to the 300 and 340 weatherby with heavy stoutly constructed bullets.  I am a disciple of PO Ackley and I guess that means Roy Weatherby too.

Don’t overlook the Vanguard series. You could buy one of those and in the savings buy several boxes of the Barnes ammo ammo if you preferred that bullet. I have shot small groups with the Barnes and the Aframes. When I first tried the Aframes I was getting around an inch group to 1 1/2” groups. I did some major cleaning and then started shooting .75-1” groups. Like I said earlier, it shot better after a few boxes of ammo. I never did get really good groups from the Select SP’s which is too bad cause the price on those are not bad. I also set a timer and wait around 10 minutes sometimes longer in between shots. Some people have good luck with the Scirocco bullet. I have not tried them yet. A couple guys have reloaded the 140 grain Accubonds for their rifles with good success.

.       I actually have given the Vanguard First Lite some consideration and may still make it my first 6.5-300.  My first Weatherby was a Vanguard in 25-06 about 30 years ago and it was amazingly accurate. I took 5 caribou with it along with numerous white tails; to many to count.  At 7 1/2 lbs and at a $1000 savings over the MarkV Ultralite  it may be just what is needed to get my feet wet with this caliber.  From what I read it is hard to handload and beat the accuracy of the Weatherby Factory loadings.   This would be a first for me as I have handloaded since I was 12 (about 45 years) and load everything from 17 Rem to 50 BMG with lots of wildcats in between.  I couldn’t tell you the last time I fired factory ammo but it would be a good way to start and collect brass for future handloads.