What does this grouping mean?

Jon Bischof

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Oct 25, 2002
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105
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Paragould, AR
I know it is true that sometimes you can affect group size or even POI on some rifles simply by holding a firmer grip or resting the forearm differently. But the last thing in the world I want is a rifle that shoots measurably differently depending on how firm I hold the forend. A rifle like that either needs some bedding to float the barrel or bedding enough of the barrel to make the harmonics consistent, or a different stock that doesn't flex when you grip it differently or adjust the rest.
 

Ryan Tockstein

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Apr 28, 2019
Messages
72
Location
Sandy, UT
Here's an update.

At this point, I'm a bit lost on what to do next and feel like I've lost the battle and possibly screwed up my gun. I'm feeling down and discouraged about it. I went to the range twice after making my previous changes. I used my load that has seemed to shoot really well in the past: h4350 at 57.5gr, sierra prohunter 150gr, fed gm210, win brass once fired then twice fired trimmed sorted and primer pockets cleaned. I try to get the primer seating depth as uniform as I can on all of them. I matched my bullets base to ogive with bullet comparator, then seated all bullets to within 0.002 of each other based on base-to-ogive length using bullet comparator. Out of both trips (5 sets of 4 shot groups each trip ) I think I only managed about 5 groups that were between 0.5" and 1" at 100 yards. Early in my development of this load, about 400 rounds ago, it shot this load much better.

- I ditched the buttstock ammo holder with the cheek pad because the straps on the bottom of the stock were catching on my rear rest pretty badly. But with the installation of my lower rings I can get really consistent face pressure on my stock so I'm not worried about that part anymore.

- I tried using my left hand very firmly on the foreend to control recoil. This too hard to do in a consistent way, so I ditched it since I've had good results in the past letting the gun free recoil.

So here's several things I've done that I'm wondering about and/or worried I screwed up my rifle.

1 - put in talley lightweight tikka rings torqued to talley's recommended torque but I didn't lap them because I don't have a lapping - I knocked the top half of the rings off my bench when installing them. I'm pretty sure I have the front/back halves matched, but I don't have any idea if the top halves are in the same orientation as they were in the package. Oops. Any way to figure out with these rings which direction the top halves are supposed to go? So, it's possible my scope is shifting in the rings but I don't know how to figure out if it is happening. Suggestions? I've thought about lapping the rings, but I don't want to screw them up. Would a thin layer of blue loctite on the bearing surface of the rings prevent slipping without messing up the scope?

2- I removed more of the rib closest to the receiver to make sure it wouldn't hit during recoil. I'm wondering if I now need to stabilize the foreend and bed the stock or if restarting load development would work. I don't love the idea of stabilizing and bedding because I don't want to add the weight and I also worry about the adhesion of the epoxy to the synthetic stock. And, that's another $60 in materials to potentially not gain anything. I did recently pick up an unused t3 stock pretty cheaply, so I can throw it in there and see if the rib pressure point was actually helping my accuracy.

3 - before my last trip to the range, I used jb non embedding paste on the bore to try to remove any potential carbon ring in the throat and to smooth the bore because it seems like my barrel copper fouls really easily. I used a 7mm nylon brush with an oversized patch with the paste. I put a stop at the muzzle so I didn't screw up the crown, gave it 100 strokes, cleaned the bore well, then did another 100 strokes with a fresh patch and paste, then cleaned well. After 20 rounds, it seems like I can seem MORE copper fouling near the muzzle.

4 - cleaning - about 400 rounds ago, my cleaning regimen after 20 rounds would be to use hoppes #9 on patches and about 20-30 strokes with a bronze brush. No copper removal. Awhile later I started using sharp shoot r tactical advantage with the accelerator after every 20 rounds with nylon brush and patches. I also used CLR (calcium lime rust remover) to remove built up carbon a few times. I think my barrel seems to pick up more copper than it used to. Maybe I should go back to just using Hoppes #9 and not remove copper?

Ugh, at this point I'm not sure which direction to go and I'm tired of nickel and diming myself with no improvement. I did have plans at some point to customize this gun with a nice lightweight stock (mcmillan, manners, or ag composite) and an aftermarket 24" barrel of the same contour. I guess I could also sell this one and get the newer tikka in od green that has a 24" barrel. I just got a raise at work, so maybe I should just expedite my customizing and I wouldn't have to worry about fiddling with the factory stock or copper in my barrel. But, that would be extremely pricey. Feeling lost and defeated and my trips to the range are now just frustrating.
 
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KurtB

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Feb 11, 2004
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434
Location
Colorado
Change scope, stop cleaning, and if that doesn't work, try a different bullet/load. I almost never clean a rifle barrel these days. And they are shooting very well. If after a few hundred rounds group size starts changing, I'll take them back down to clean steel.

If none of that sounds appealing, trip this one and buy or build something a bit better. I added up range trips, gas, reloading time and supplies, etc on a few guns. Adds up fast. That was when I just went to McMillan stocks, good gunsmith, great barrels and scopes, and most of my load development got down to about 20 rounds. Well worth it to me.
 

Rflshootr

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Jan 20, 2008
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119
Location
Baltimore, MD
A bore can be over polished and make it copper foul more. Go back to a regular cleaning with solvent and brushes. Also, your groups probably opened up because the throat is getting some wear now. Try seating your bullets .005 closer to the lands and see if that doesn't tighten it back up with the 57.5 load.
 

Ryan Tockstein

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Apr 28, 2019
Messages
72
Location
Sandy, UT
Also, your groups probably opened up because the throat is getting some wear now. Try seating your bullets .005 closer to the lands and see if that doesn't tighten it back up with the 57.5 load.
That's an interesting thought. I think I've got 550 grounds down the barrel at this point. Is it possible for the throat to wear that much in a stainless barrel after 500 rounds even if I usually only let the barrel get warm while I'm shooting and not hot?
 

Rflshootr

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Jan 20, 2008
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Baltimore, MD
Yes. Stainless isn't a cure-all and actually wears faster then chrome moly barrels, everything else being equal. 50K-60K psi and a hot flame at the throat isn't any ones friend. Try it and let me know what you find out.
 
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Ryan Tockstein

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Apr 28, 2019
Messages
72
Location
Sandy, UT
Yes. Stainless isn't a cure-all and actually wears faster then chrome moly barrels, everything else being equal. 50K-60K psi and a hot flame at the throat isn't any ones friend. Try it and let me know what you find out.
I went back almost to square one as much as I can at this point and am going to the range today.

I loaded up the best load I've found so far, but used cci200 primers since that's what I was using originally. I didn't actually put a bullet into my chamber to measure what my base to ogive distance might be now, but I loaded this round of 20 to be about 0.005 closer to the lands than what I had been doing.

I also put my action into the T3 stock I bought a bit ago since that one is completely unmodified. After installing the action into both my t3x stock and the used t3 stock several times, I'm thinking it's possible it could be my stock's bedding surfaces around the recoil lug. The action slips into place in my t3x MUCH more easily than the used t3. It seems like a much tighter fit in the T3.

I also only cleaned my barrel with hoppes #9 and a bronze brush after the last 20 rounds, the way I'd done early on.

We'll see how it goes today!
 

Ryan Tockstein

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Joined
Apr 28, 2019
Messages
72
Location
Sandy, UT
Change scope, stop cleaning, and if that doesn't work, try a different bullet/load. I almost never clean a rifle barrel these days. And they are shooting very well. If after a few hundred rounds group size starts changing, I'll take them back down to clean steel.

If none of that sounds appealing, trip this one and buy or build something a bit better. I added up range trips, gas, reloading time and supplies, etc on a few guns. Adds up fast. That was when I just went to McMillan stocks, good gunsmith, great barrels and scopes, and most of my load development got down to about 20 rounds. Well worth it to me.
I REALLY want to not clean my barrel at all... but I'm terrified of getting that layering of copper/carbon/copper/carbon that is apparently really hard to remove. So I'll give it a few more efforts with only cleaning with hoppes to get the carbon out.

As far as scope goes, I don't have another scope to put on and test and am very hesitant at this point to dump money into another scope. I wouldn't mind selling my vortex and trying something else, like an SWFA since it sounds like those are pretty bullet proof, but it also seems like vortex doesn't resell all that close to retail since there's always so many sales, so many used ones for sale, and so many people claiming to have quality issues with them nowadays.

I was thinking there must be a way to test my vortex scope that doesn't really on shooting. Are there any clever ways of mounting a scope to a board and subjecting it to shock such as what it would experience during recoil and being able to check if it's maintained zero? I don't do any dialing with the turrets at all, so they're out of the picture. If it's my scope, it's either the scope itself or it is slightly shifting in my rings.
 

Jon Bischof

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Joined
Oct 25, 2002
Messages
105
Location
Paragould, AR
I agree with Rflshootr, If you change three things before you shoot, you will never know what the problem was even if you manage to correct it.

Loook to see if you are still getting two distinct separated groups next time you shoot.

Changing too many things at once will drive you nuts. Systematic is the way to proceed. Let me know how you make out today.
 

Ryan Tockstein

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Joined
Apr 28, 2019
Messages
72
Location
Sandy, UT
I agree with Rflshootr, If you change three things before you shoot, you will never know what the problem was even if you manage to correct it.

Loook to see if you are still getting two distinct separated groups next time you shoot.

I agree as well. I should know better... I work in a scientific field so I SHOULD have the patience to apply that to my hobbies :/

I attached a couple pictures of my targets. The one without writing is from my trip a few days ago where I had lost all hope. The one with writing is from today.

While today's groups overall aren't stellar, they are way better than a few days ago. Since I modified my rests with electrical tape to be tight on my foreend and buttstock, I've found it a bit hard to create consistent pressure on the stock. I removed the tape from my front rest and on the last group I just sat the buttsock down into the ears rather than pushing it down in them and focused on putting as little pressure on the stock as possible. I think that helped a bit. I'll keep everything the same next week and do what I did on the last group to see if it's consistent.

I wonder about the wandering poi on today's target though. Could a change in stock grip pressure (myself and my rests) be affecting my poi that much? My gun is 7.5 lbs, so that seems reasonable, I think. Or, would that be more indicative of my scope moving shifting in the rings or not holding zero?
 

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