7mm RM Grouping question

[HandgunHTR]

Yea good point, my waiting time statement may be a little misleading. For each group I shot the 3 shots consecutively not really waiting much between shots, It was in between groups that I waited until the barrel cooled. I'm certainly not beyond flinching but I don't think I am, I usually only shoot 3, 3 shot groups with my bigger calibers for that exact reason. I do not have a brake on this one.

I would guess that it is a barrel heating problem based on your reply.

If this is going to be purely a hunting rifle, then I would shoot “cold bore“ groups. Shoot one, let the barrel cool 10-20 minutes, then shoot another, etc. If you have time, shoot a couple 5-shot groups that way. It will give you a good indication of the cold bore accuracy of your rifle, plus it will tell you where that first shot is going to go, which is the most important shot on a hunting rifle.

 

[ROBARRC50]

This is a target from a ruger 77mk11 7 mag pencil barrel. Its a 1& 9.5 twist. Shooting berger 168 classic hunters they are a little shorter than vld. Your holes in target look like the bullet was stable at that distance. Dont think its a twist issue. Test seating and maybe retry ladder test with half grain increments i use .3 myself. When i found my accuracy area and everything was dialed i did a seating test from .020 off to .160 off lands. Groups were still smaller than yours at 150 yards but they looked like yours when the seating was way off . Maybe you have already done this to get to where you are currently at. If so good luck in fine tuning the load. In reality if it shoots consistently poa poi thats plenty accurate for field work out to realistic distances.

 

[Landyboy]

Nice shooting! I am going to try smaller load changes on my next range trip. I have them seated about .040 off the lands now but I am going to play with the seating as well.

 

[JDinFbg]

Its a B&C stock and it has pillars however I think the channel can be better, It's free floating but barely. I think I will open it up a little more to get the floating more constant. Then I will bed the lug and see what happens. I do agree I'm probably chasing groups when I should be looking at the first cold shot. It is getting better, when I started with Hornady ELD-x's and the factory stock I couldn't get it shoot a half decent group at all.

When I saw your OP, my first thought was that as the barrel heated up it may have started touching the stock somewhere. So your thought to open up the barrel channel is probably a good place to start. One way to verify if this might be the issue is to do the 'dollar bill test'. If you can freely slide a dollar bill between the barrel and the stock when it is cold but cannot do that after the barrel gets hot, that would confirm you have a stock-touch issue. You noted you were shooting Berger VLD bullets. Berger has a test procedure on their website about how to identify the jump range over which VLD bullets shoot best in a given rifle. VLD bullets generally shoot best with some jump, so you may want to review the Berger article and do some jump testing to see if your VLD's are in the 'sweet spot' with respect to jump.

 

[std7mag]

Nice shooting! I am going to try smaller load changes on my next range trip. I have them seated about .040 off the lands now but I am going to play with the seating as well.

Smaller powder changes, follow the seating depth test in Bergers manual.

My Savage 111 likes the 168gr VLD up close & personal with the lands. 0.005".

I wouldn't worry about the 1:9.5 twist rate, as that's what mine is & shoots the 168gr VLD just fine.

 

[Landyboy]

I opened up the channel, bedded the lug area and I'm headed to the range today. I'll give an update when I get back.

 

[Coyotefurharvester]

On the box, 1/9 or faster twist. Only higher elevation, velocity will work the twist rate in your flavor. Shoot some at 300. Gets expensive using bullets that don't match the barrel.

 

[wbm]

There is nothing "wrong" with the groups you posted. In fact, triangle shaped groups in predictable patterns like in your photos means that rifle will be a "shooter" when the harmonics are right.

Personally I would not touch a thing on that rifle! It is grouping well now!
Just keep playing with Retumbo and the VLD.

 

[waterfwlr]

Your rifle can do better than that with load development. I have the same rifle in the same caliber. I did put the Timney trigger spring in though. My 2 best powders are 4831 and RL22

 

[Landyboy]

Range Report
I was at the range and shot 3-3 shot groups allowing the barrel to cool about 20 mins between groups. Things I changed before I went were opening up the barrel channel more and bedding the lug. Last time I shot 3 consecutive groups of 3 with Retumbo x0.0 grains, X0.6 grains and X1.2 grains in that order. This time my loads were X9.8 grains, X0.2 Grains and X0.6 Grains (smaller increments. The first group was pretty good lol, second not bad and third opened up a little however I cant rule out a slight flinch on the last group. For consistency I am going to shoot the exact same loads next week on a day similar in weather to today.

I did upgrade the spring as soon as I got the rifle, It did help alot.

 

[David Milisock]

Don't misunderstand because I know we love the challenge of getting that rifle shooting bragging size groups. As hand loaders who shoot rifles it's how we're made.
Seems to me you would be better served by shooting a one-shot target every day for three days.
Overlay those three shots and see what your "hunting group" comes in at.
It's a hunting rifle and I like for a hunting rifle to deliver hunting rifle results. I don't really care if it shoots small groups; it's the first shot (cold bore) that counts.

I had a Savage 06 that was that way, first 2 shots nearly always touched. From there on it was bad to worse. Two shot groups over layed from day to day or week to week were great.

Hunting rifle, who cares.

 

[Idaho-Lefty]

Good Job, on doing the Gunsmithing work, on your Rifle,..
Take, that, First Load out to, 200- 300 yards and see IF it, is still grouping, "well" !
You are checking, to make SURE that, the Bullet,.. IS,.. "stabilizing".
A "good Rifle" and Load, should Print, into 1.5 inches at, 200 Yards ( 3/4 MOA ) IMO
You look to be, on your Way !

 

[DocCarbon]

IMO : For whatever that's worth , I believe a barrel should hold POA and group decently for #5 rounds Magnum or Not . This is off the ground on a sand bag ,as I was adjusting the Nikon I had mounted .

My Commercial 1964 3000L 7 RM ,will do as well and those barrels are pencil profile again IMO .

My Hunting standard is #5 shots a dime will cover at 200 meters or yd. . I'd have to look the load up but I know their 160 Gr. Nosler with H870 ,as I still use that powder in ALL of My 7RM's .