7mm Accuracy

[RoJo]

...seems like it gets worse the hotter the barrel gets.

Your SPS has a synthetic stock, right? I had a Rem 700 do that once, but it had a wood stock. It started after a bear hunt where I was hunting in the rain for 3 days. Apparently the stock warped, which caused a pressure point. The warmer the barrel got, the crazier it would shoot. A gunsmith re-floated the barrel, and he said he had to remove quite a bit of wood to do it. After that it was fine.

 

[CT Barrett]

Yes it is a synthetic stock it is not free floated and had a pressure point at the end on the barrel. I have researched it a bit and they say the stock is junk and not to try and bed it as it is too weak overall. I bought the gun new in box in May 2009. The bullets I used at the beginning were taken out of production and I suspect this group problem may have happened with the change from interbonds to SST bullets.

So follow up to what I have tried so far...
Last weekend I bought some Montana Extreme Copper killer. Boy is it strong. It has a warning label that says "strong odor", so I immediately popped the cap and took a wiff. Whew after I picked myself off the floor I followed the instructions and got tons of blue patches out of the barrel. I continued until nothing but clean came out which didn't take much.
I thought I would start over with my load charges and see if it made a difference. I loaded 5 rounds (to get some cold oily bore shots out) at 59 grains and 3 rounds each from 60 grains to 64 grains . I shot groups from a vanguard steady aim and got 3" groups in each I stopped at 62 grain loads and said to hell with wasting powder. Another guy at the range said check your scope.
I went home and checked the torque on the scope mounts and bases then proceeded to remove the scope and shook it to listen for any noise from loose internals. Nothing heard or felt. So I remounted with blue loctite. Also found out that I have Leupold std bases and rings which is different than I said at the beginning of the post.

After talking with more people I realized that maybe I should check my overall cartridge length using the ogive instead of the bullet tip and determine my actual freebore. I am not sure this would actually be enough to cause problems if it wasn't ideal but I at least want to get a better handle on what it is. I was told to start with 0.015" off the lands and work backwards and forwards 0.003" at a time. I have the hornady OAl gauge but not the bullet comparator which I would like to get since the poly tips seem all over the place to be using them for measurements at the tip.

I also heard remingtons, in the last 10 years are terrible for the barrel bore not being centered in the barrel, meaning one side can be thicker and cause problems. Mine has rifling and definitely has a good crown.

So far I do not think its the scope and don't have the money to buy another one at the moment. I could swap scopes with my 243 which has the exact same scope.

My plan of action in order is as follows one thing at a time.
1. Work up a standard base load and try some different bullets, interbonds in 154 grain are still mostly impossible to find.
2. New stock with aluminum pillars and bedding and floated barrel
3. Aftermarket trigger
4. Aftermarket barrel
sell the gun at a loss?

I just bought an 85mm vortex razor spotter so I am gonna have to wait and accumulate some funds for the stock and trigger.

 

[CT Barrett]

Well I ordered a timney trigger and a bell and carlson fiberglass stock. The stock has a full aluminum frame inside but it also has the lugs for barrel pressure points. I also bought some berger 168 grain VLD hunting bullets and h1000 powder. Then got some hornady dies plus a neck sizer die as I heard my RCBS ones are junk. I do plan to skim bed the action in the new stock and float the barrel. Worst case I can put shims back in the for-end for the pressure on the barrel if needed later. I will follow up if I ever solve the problem.

As a follow up I started using a journal and measured stuff. Also got a bullet comparator for my hornady overall length gauge. I discovered that I originally loaded the interbond 0.010" off the lands and the SSTs at the lands. So I reseated the SSTs I had left from my ladder test 0.010" off the lands and will try them. I have had a lot of bad weather for shooting lately so I am pretty much starting all over with the new stock.

 

[cooperjd]

Nice. Be sure to check out Ernie the gunsmith website for the little spacers to "pillar bed" your action even with the aluminum block. I used those along with several cut strips of paper to check and make sure my action was only touching at the pillar spacers. This way when you bed your be bedding a stress free action as well as a free floated barrel

 

[CT Barrett]

Nice. Be sure to check out Ernie the gunsmith website for the little spacers to "pillar bed" your action even with the aluminum block. I used those along with several cut strips of paper to check and make sure my action was only touching at the pillar spacers. This way when you bed your be bedding a stress free action as well as a free floated barrel

I did that very thing. The Ernie's spacers are on their way and I just finished inletting the new stock and removing the pressure pads on the forend. I used some old silver lipstick that worked excellent for finding contact points and used various size sockets to sand the high spots out. The B&C stock was tight in the action and making the barrel out of center in the barrel channel. It was well fit in the lug and pillar area but by taking the side and barrel pressure points out the action sits in there much better. I can get paper through everyplace but the pillars.

I did something really stupid before I ordered Ernie's spacers. I got some really thin stainless washers 0.050" and put them between the action and my old SPS stock to curve them to the action by tightening the screws. Long story short I ended up stripping the rear action bolt and had to drill it out. In the process of trying to get the trigger guard off I broke it in front of the floor plate hinge-it's cheap pot metal. I can't believe how much a replacement trigger guard costs, I found the cheapest Remington replacement at Brownell's for about $110. So now my bedding job will have to wait. I also ordered some more modeling clay, new action screws, a wheeler scope mount lapping kit that comes with the wheeler torque wrench, plus some power custom bedding studs. There shipping is incredibly slow so its going to have to wait until next weekend. Good thing its not the middle of hunting season.

 

[CT Barrett]

Update...

I glass bedded the new stock last weekend. Floated the barrel and used ernie the gunsmiths bedhead spacers and instructions for the pillars. Installed the timney and left set as delivered at 3 lbs. I am using Dan newberry's method of optimum charge weight to find the best load. I tried the test on 168 berger vld hunting bullets and the hornady eld-x 162 grain bullets both using H1000 powder ranging around 67 to 71 grains in 1% increments. I just shot 80 rounds this weekend over two days. So far the best thing I can conclude is the work improved a few groups from (prework) 3 shot 1.9" groups to 5 shot 1.6" groups @ 100 yards but only on a few charge weights of both bullet types. I used a caldwell tack driver and rear sand bag instead of the vanguard steady aim device for testing.

A also verified I could still shoot by shooting a 3/4" group with my glass bedded model 70 243. I have came to the conclusion that its my marksmanship specifically knowing my lightweight rifle kicks like a mule and I am scared of the recoil and just can't handle the pain. I am not necessarily pulling the trigger most of the time but having a hard time focusing on the target anticipating the recoil. I tried really hard today to take my time but I think I need to install a muzzle break and gain some confidence. I really hate to need ear plugs while hunting but I guess if it will help me shoot better I will make that compromise. Pretty disappointing considering the money spent but if its me I would bet those changes made some improvements.

I would like to hear suggestions on a good one that doesn't have a bottom port to hit the ground and stir up dust.

 

[Idaho Sandman]

Just curious, but have you shot groups at 200yds? My 7RUM with 168 VLD will only shoot 1"+groups at 100 but will shoot sub 1" at 200. Best I measured was a 3 shot group under 5/8" @200. I emailed Berger and they stated that the bullet has yet to stabilize at 100 and can result in a little bigger groups at that range. They suggested to group at 200 and adjust accordingly.

 

[Axlrod]

Here is the place I have bought a few Brakes from: Blank Title - Home
They are reasonable and they work.
As far as having to use ear plugs any centerfire is going to ruin your hearing so I have always used ear plugs or muffs while hunting. The Brake will make your gun a joy to shoot and should improve your accuracy.
But it may be that your barrel will not shoot better than it has- some guns just don't shoot. I always buy a box or two of premium ammo for a new rifle and if it doesn't shoot decent the gun goes bye bye before I waste a bunch of time and $ on it. If it shoots good I have a base line with the factory stuff to go back to if I change anything.

 

[Axlrod]

Just curious, but have you shot groups at 200yds? My 7RUM with 168 VLD will only shoot 1"+groups at 100 but will shoot sub 1" at 200. Best I measured was a 3 shot group under 5/8" @200. I emailed Berger and they stated that the bullet has yet to stabilize at 100 and can result in a little bigger groups at that range. They suggested to group at 200 and adjust accordingly.

BULL!
Bullets are as stable as they are going to get when they leave the muzzle.
Brian Litz is an aerospace engineer and a champion long range shooter, runs Applied Ballistics and is the guy that designs Berger bullets and he has a standing invitation to anyone that says their gun shoots smaller groups at longer range than it does at shorter range to come out to Michigan and prove it- he will pay for your trip if you can. No one ever has and he says he has never seen it.
Here is a link to what he says about the subject and how you can test it.

Applied Ballistics Shoot Thru Target Challenge | Shooters' Forum

 

[Idaho Sandman]

Not bull and I have nothing to prove. Just stating what I observed and when I emailed them several years ago, that was their response. I have zero reason to embellish. I was very disappointed in accuracy at 100 yds and as such decided to inquire about it. I will contact him directly then and ask him what he thinks. I had never heard of such a thing and was surprised by their answer. My gun groups better at 200 than 100. Maybe I shoot better at 200, even though I didn't have the same issue with 150 scirocco. I'm just going off what I saw and what was mentioned to me.

From the post you quoted:
"we still can't claim with certainty that it doesn't happen because we haven't tested every possible rifle and combination". There are still many shooters swearing they see it on a regular basis"

 

[elkguide]

I have a 7X57 Ruger Model 77 that "seems" to be in this same category...... ie: 1 1/4" groups at 100 yards and still 1 1/4" groups at 200 yards. It makes absolutely no sense to me as once the projectile leaves the barrel it has stabilized and other than trajectory, the path of that bullet is determined, based on how well the projectile stabilized in the barrel and providing the crown of the barrel didn't influence it.

I love these true mysteries.

 

[Idaho Sandman]

I have a 7X57 Ruger Model 77 that "seems" to be in this same category...... ie: 1 1/4" groups at 100 yards and still 1 1/4" groups at 200 yards. It makes absolutely no sense to me as once the projectile leaves the barrel it has stabilized and other than trajectory, the path of that bullet is determined, based on how well the projectile stabilized in the barrel and providing the crown of the barrel didn't influence it.

I love these true mysteries.

It's crazy as I don't see it with my 150grn scirocco loads.

 

[elkguide]

Having just read through this entire thread let me begin by making two observations.

1. I love Hornady SST's and have used them from coyotes to elk.
I have a custom built .284 Win that is a consistent <1 MOA rifle BUT with SST's, > 2 MOA on a very good day.

2. When using less than 70 grains of powder, a magnum primer is not needed.


If you have developed a serious aversion to the recoil of the 7 Mag , there are lots of ways to reduce the felt recoil, from shoulder pads to putting a bag of lead shot between your shoulder and the rifle and even having a less recoil sensitive friend shoot the rifle for you.

My immediate suspicion is that your rifle just doesn't like the SST's
but isn't it fun trying to understand the dynamics of a particular rifle?!?!?

 

[Axlrod]

Not bull and I have nothing to prove. Just stating what I observed and when I emailed them several years ago, that was their response. I have zero reason to embellish. I was very disappointed in accuracy at 100 yds and as such decided to inquire about it. I will contact him directly then and ask him what he thinks. I had never heard of such a thing and was surprised by their answer. My gun groups better at 200 than 100. Maybe I shoot better at 200, even though I didn't have the same issue with 150 scirocco. I'm just going off what I saw and what was mentioned to me.

From the post you quoted:
"we still can't claim with certainty that it doesn't happen because we haven't tested every possible rifle and combination". There are still many shooters swearing they see it on a regular basis"

It is very possible that you shoot better at 200 than 100 but the 2 target challenge ( place a target at 100 and one farther out 2 or 300 yds directly behind and shoot through the first into the second) this will take the shooter out of it and show you what the gun will do.
There has been a LOT of testing with the 2 target groups and it doesn't change. Every 2 target group is the same shape and holds true moa ( if its 1" at 100 it will be 2" at 200)
You cant compare 2 different groups to each other. Do the 2 target challenge and you wont have a smaller group at longer range with the exact same group.

Think about it: if at 100 yards you have a group that is 1" lets say 1 is dead center 1 is 1/2" left and 1 is 1/2" right. the bullet that is 1/2" left of your intended target is off course, it didn't know where it was going when it left and has no way off getting back to where you wanted it to go and will continue "off course" at 200 yards it will be 1" to the left.

 

[CT Barrett]

Having just read through this entire thread let me begin by making two observations.

1. I love Hornady SST's and have used them from coyotes to elk.
I have a custom built .284 Win that is a consistent <1 MOA rifle BUT with SST's, > 2 MOA on a very good day.

2. When using less than 70 grains of powder, a magnum primer is not needed.


If you have developed a serious aversion to the recoil of the 7 Mag , there are lots of ways to reduce the felt recoil, from shoulder pads to putting a bag of lead shot between your shoulder and the rifle and even having a less recoil sensitive friend shoot the rifle for you.

My immediate suspicion is that your rifle just doesn't like the SST's
but isn't it fun trying to understand the dynamics of a particular rifle?!?!?

Interesting I may never shoot the SST again. I also tested the eld-x and vld hunting bullet with 1.6" groups at best. I really think its me though.

After watching all the terminator products demonstration you tube videos of their terminator T2 brake I am impressed.

T2 Terminator Muzzle Brake compared to others - YouTube

Terminator Muzzle Brakes on a 7mm Rem Mag - YouTube

T2 Terminator Muzzle Brake on a 7mm Rem Mag compared to a 243 - YouTube

I have not shot at 200 yards. My belief is the groups would be twice the size. I am not trying any farther range until I am sub MOA at 100.

 

[GKPrice]

BULL!
Bullets are as stable as they are going to get when they leave the muzzle.
Brian Litz is an aerospace engineer and a champion long range shooter, runs Applied Ballistics and is the guy that designs Berger bullets and he has a standing invitation to anyone that says their gun shoots smaller groups at longer range than it does at shorter range to come out to Michigan and prove it- he will pay for your trip if you can. No one ever has and he says he has never seen it.
Here is a link to what he says about the subject and how you can test it.

Applied Ballistics Shoot Thru Target Challenge | Shooters' Forum

Litz is talking "science" and so many shooters going back many years are talking "applied experience" - both can be true

 

[GKPrice]

It is very possible that you shoot better at 200 than 100 but the 2 target challenge ( place a target at 100 and one farther out 2 or 300 yds directly behind and shoot through the first into the second) this will take the shooter out of it and show you what the gun will do.
There has been a LOT of testing with the 2 target groups and it doesn't change. Every 2 target group is the same shape and holds true moa ( if its 1" at 100 it will be 2" at 200)
You cant compare 2 different groups to each other. Do the 2 target challenge and you wont have a smaller group at longer range with the exact same group.

Think about it: if at 100 yards you have a group that is 1" lets say 1 is dead center 1 is 1/2" left and 1 is 1/2" right. the bullet that is 1/2" left of your intended target is off course, it didn't know where it was going when it left and has no way off getting back to where you wanted it to go and will continue "off course" at 200 yards it will be 1" to the left.

admittedly they were both shooting Berger VLD's (and lighter than I would choose to use on game) but I've done that 2 target test myself - 2 of my rifles, both factory guns with the usual aftermarket stuff done and both times the 200 yard targets were virtually the exact same grouping as the 100 yard targets showed, I never tried it at 300 - I understand what you say about WHERE the 200 yard group is on the cardboard, zero'ing is done AFTER you vet the rifle and load just as you say - those aren't the only rifles I've had that happen with though ...... ALSO, EVERYTHING has to be pretty much perfect when done to get even "sort of" consistent results

 

[cooperjd]

if nothing else works i guess you could try truing the action and bolt, and setting the barrel back one turn and correcting headspace, should be around $300 from somewhere like: About Us - Services

at some point this year i think i'll try to remove the buttpad from my B&C and replace with a sims, i just gotta figure out how to remove and replace as i can't find any screws in the B&C...looks like i'll have to freeze it and try to pop off the old one, then figure out what new one will fit and go from there...

witt machine makes a slide on brake, you could get comfy with that and hunt without a brake, just confirm zero does not change...

 

[CT Barrett]

at some point this year i think i'll try to remove the buttpad from my B&C and replace with a sims, i just gotta figure out how to remove and replace as i can't find any screws in the B&C...looks like i'll have to freeze it and try to pop off the old one, then figure out what new one will fit and go from there...

My B&C buttpad has screws, look very close and you should see 2 tiny cuts in the rubber. That is where the screws penetrated. the heads will be in there a ways so you might have to try and get something to pry the slits open to see what driver is needed. I am considering a new buttpad as well.

Thanks for the slip on idea and action work.

I have been analyzing my data and while its not great I did record velocities on every shot and using a combination of ladder test method, OCW and good old best groups method I think I have identified a good charge weight to fine tune with each bullet.

 

[USPcompact]

BULL!
Bullets are as stable as they are going to get when they leave the muzzle.
Brian Litz is an aerospace engineer and a champion long range shooter, runs Applied Ballistics and is the guy that designs Berger bullets and he has a standing invitation to anyone that says their gun shoots smaller groups at longer range than it does at shorter range to come out to Michigan and prove it- he will pay for your trip if you can. No one ever has and he says he has never seen it.
Here is a link to what he says about the subject and how you can test it.

Applied Ballistics Shoot Thru Target Challenge | Shooters' Forum

Litz knows his stuff.

He's got a standing offer to pay the way there and back for anyone that can demonstrate the effect. So far no one has taken him up on this.

Of course, no one has claimed the various rewards offered for Bigfoot and Nessie, either.