What does this grouping mean?

Bill Cauley Jr

Formerly 'unclewilly'
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I guess some details would help!

It's a 30 06 tikka t3x superlite stainless barrel synthetic stock. I used a Dremel to remove extra stock material around the forearm to give it extra float. I can slide several dollar bills all the way back to the receiver without hitting anything.

Strangely it does seem that it's shots 1&3 and 2&4 grouped together more often than not. This group was part of a load development set. The way I'm doing these is I'll shoot one Rd of each load, 5 different loads. The order is 1 to 5, 5 to 1, 1 to 5, 5 to 1. I started doing it this way because I would do each as a 5 shot string giving a 5 minute break between to cool. Now I just do 1 shot every 3-4 minutes and that's adequate to just keep the barrel warm. Again, I have had these groups before and after changing shooting patterns.

I do handload. Here's what they are:
Winchester brass, 3 firings, not annealed
Fed gm210 primers
H4350 (63.0gr)
Sierra pro Hunter 150gr
Started using my hornady comparator to get all my seating depths the same. So for these, they're all seated to be 2.731 base to datum, +/- 0.001

My rest is a Caldwell rock Jr and the bunny ear rear bag. I modified both to give a much more firm grip on my stock and be much more stable. These groups would happen before I did that though.

I don't have a good cheek weld because my scope is sitting too high... Therefore I sometimes find it hard to duplicate the amount of downward pressure I'm placing onto the stock at the grip.

Here is a few targets
You just said it cheek weld I don’t believe your positioning your face in the same place if you are not touching you are not repeatable
 

Bill Cauley Jr

Formerly 'unclewilly'
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Looks like time to break out the vet wrap and packing foam. Get your cheek weld right. Lay your head completely relaxed behind the scope, on target and close your eyes, after a brief nap ( 5 or so seconds), look again and see where you are. If not on target, change something in your cheek rest. More foam, or less until you are on target when you open your eyes.
Yes what he said__^^^^^^^
 

Tensilon

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Dec 29, 2010
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Northern Minnesota
The foreend of my stock definitely flexes with some effort! Not a lot though. My recoil lug is tight as can be!!! When I've removed it from the stock, I've had to use pliers to grip it to get it out. Would the lug still need bedding?
Any flex in your forearm can lead to grouping issues. I see aushunter1 feels the same way I do about T3 stocks and like I said earlier my best thought in regard to the double groupings is that it probably has to do with the weak forearm that is flexing when you settle in and shoot. Sounds like you know your way around building an accurate cartridge for the most part. If you bed a Tikka stock, the recoil lug must be bedded in a very particular way. I also have 2 Tikkas, one in 6.5 creed and one in a 300 win mag but both are the hunter models with wooden stocks. The 300 is bedded to about an inch or a little more down the barrel. It is also pillared and the lug is permanently bedded into the stock. The 300 lays rounds in consistently around 0.25 to 0.36 of an inch. The creedmoor I am working on bedding and pillaring right now. When bedding the recoil lug of a T3 the top and the rear face of the lug need to be clear of the action while the front face of the bedded lug needs to be in full contact with the action in order to return to battery properly. In other words... the top and rear of the lug needs to be taped when bedding and the front of the lug needs to fit firmly against the action i.e no tape. When I say the action I mean the tiny slot that the top of the recoil lug fits into. Also, the T3s do not have a free floated barrels from the factory. There are pressure point ribs on the sides of the stocks. These help the factory rifle immensely and they are not located at the forearm tip. Tikka has not designed the stock to be free floated. If you have removed the pressure points from the plastic stock then you have effectively removed what Tikka put in there to make the rifle more consistent. Really, one should never free float a plastic stocked rifle without bedding the rifle. One also needs to fill the forearm of the stock with a light weight bedding compound like I mentioned earlier i.e. Match Grade plastic stock stabilizer to stop it from flexing. If you have never bedded a rifle stock it may just be easier to buy a decent aftermarket stock with a full length aluminum bedding block in it. From what I understand not many smiths are really good at bedding the Tikka lug in the manner that it needs to be bedded... I may be wrong about this as the correct method of doing this has probably gotten around somewhat. You are more than likely capable of doing it yourself but one needs to understand the way a floating recoil lug works in order to do it correctly. Also, if you have ever torqued the actions screws on a plastic Tikka stock to over 45 inch pounds you have already splayed out the plastic stock. The only solution to saving the stock is to properly bed it and stabilize it. There are issues with flexy plastic stocks that must be addressed. So it's easy to go down a rabbit hole by chasing all sorts of issues with a rifle that groups poorly however, first and foremost you need a stable platform from which to launch your bullets. I don't think too many folks, especially on this forum, will disagree with that statement.
Two books would help you out immensely: The practical guide to bolt action rifle accurizing and maintenance and the practical guide to long range hunting rifles by Nathan Foster. In these you will find a wealth of information in regard to what works and what doesn't for most all brands of rifles but also specifically in regard to the problems inherent to plastic stocked T3s. I know I sound like an ad for this Kiwi's website.... but the man knows his business and what he advises has worked for me every time. Ballisticstudies.com. Straight up guy and speaks and writes in easily understandable terms. Don't give up... Tikkas can be very accurate rifles and the actions are smooth as glass.
Best of luck with your rifle Ryan. Let us know what finally works for you.
Tens :cool:
 

Greyfox

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Given the barrel rifle/barrel weight, and looking at the group dispersion, I would try to eliminate hold/support as the issue. The majority of the times I have experienced the target patterns you show, has been with light rifles. What is believed to be a good rest can simply bring more consistency to the split groups. Keep in mind that the barrel will move 1/8-1/4” before the bullet leaves the barrel. Try varying degrees of forearm control in addition to the cheek weld and grip pressure. Check for differences in group pattern. If it persists, the problem, IMO, may be mechanical which. has been well covered in this thread. IMO...
 
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Ryan Tockstein

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I got some lower rings that I installed and a buttstock ammo pouch that has a raised cheek rest. We'll see how it a better cheek well works out! One thing I'm worried about though, is potentially having the webbing straps on the bottom of my ammo pouch catch on my rear rest during recoil (I let my left hand sit on the bench in front of the rear rest and let the gun free recoil . The two items I have are in the pictures below, but I improved the rear bag awhile ago using electrical tape on the ears to firm up the hold and stability on the stock and I also put a 1" x 6" board on the bottom of it to make the whole bag more stable.

1580308561187.png 1580308613079.png

When removing my action from the stock, I also noticed that my barrel had some marks on it from it hitting the pressure point rib closer to the receiver, which I'm 98% sure it was happening during recoil and possibly touching after the barrel warmed up. In the tikka synthetic stocks, there are two pressure point ribs in the foreend. Not long after I got the gun, I trimmed these down to free float it as well as a bit of the barrel channel on one side that was contacting the barrel. I read quite a few accounts of people improving the accuracy of their tikka by removing those ribs and it seemed to shrink my group sizes after I did so. But I apparently didn't trim the one down farm enough. So, I went ahead and trimmed the one that was making contact a bit further to hopefully eliminate any contact during recoil and when the barrel warms.

Unfortunately, I changed too many things at once for methodical problem solving. Pretty dumb of me!! :oops: But, I'm ok with starting at square one. So the changes I made for the next round of shooting are: lower scope and raise stock comb height, removed more stock material that was making contact upon recoil and/or barrel warming. I'm excited to see what happens!

If these changes don't eliminate the odd groups, I'll probably stabilize the foreend with the stock stabilizer someone mentioned, as well as bed the action. Does anyone know of a lightweight resin that can be used as the foreend stock stabilizer that is readily available at stores rather than ordering the stuff online through Nathan Foster's ballistic studies web site? I figured I could use a regular 2 part epoxy like JB weld or similar, but I want to find one that is lightweight so I can keep the weight of my rifle down. I'm not looking to turn it into a heavy gun.
 
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Ryan Tockstein

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Given the barrel rifle/barrel weight, and looking at the group dispersion, I would try to eliminate hold/support as the issue. The majority of the times I have experience the target patterns you show, has been with light rifles. What is believed to be a good rest can simply bring more consistency to the split groups. Keep in mind that the barrel will move 1/8-1/4” before the bullet leaves the barrel. Try varying degrees of forearm control in addition to the check wel and grip pressure. Check or differences in group pattern. If it persists tThe problem, IMO, may be mechanical which. has been well covered in this thread. IMO...

This, I think could very well be the culprit. My bare gun is somewhere around 6lbs and my scope is in the ballpark of 21 oz. So, my gun is pretty darn light. I try my hardest to make my holding pressure and everything identical for each shot, but it's pretty hard to do, and the recoil of the gun with muzzle jump is often different on each shot even with my best shooting load.
 

fiftybmg

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Johannesburg, South Africa
I can see three things to consider.

First, the group patterns appear to me roughly repetitive. A similar group pattern will appear on multiple targets.

This suggests you are changing the pressure points on the rifle cyclically, trying one grip for one string, another grip for the next, etc, till you come back to the first again. if the stock is flimsy, the grip change becomes significant.

Getting a cheek rest will help you settle on one way to hold the rifle, ideally without introducing any flex in the stock.

Second, these patterns are obviously affected by the various loads under development, some loads will have a much lower velocity spread than others and group better. I don't see velocity numbers in the thread or on the pictures, but from your powder data, your best groups are up to 58 grains, which suggests that those have the lowest shot-to-shot speed variation. The higher the powder charge, the bigger the group appears to be. Focus on refining those lower charges. A quick way to improve ES is a better [ benchrest ] primer.

Thirdly, if you have a can on the end. It is a variable that can cause load development headaches when groups are involved, either by working loose or getting clogged up. Take it off untill after the load development is complete, then adjust the scope for the POI shift it causes.

The T3X is a factory sleeper, it is accurate out of the box. If you feel you have to to prove this, buy a box of factory match ammo.
 

KurtB

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Had a Leupold do that to me a few times. Swapped scopes and life was good. I never saw what scope you were using.
 

Tensilon

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Does anyone know of a lightweight resin that can be used as the foreend stock stabilizer that is readily available at stores rather than ordering the stuff online through Nathan Foster's ballistic studies web site? I figured I could use a regular 2 part epoxy like JB weld or similar, but I want to find one that is lightweight so I can keep the weight of my rifle down. I'm not looking to turn it into a heavy gun.
If you find something that will do that...let me know please Ryan. JB and such will add quite a bit of weight. I don't believe you can buy his stabilizer in stores but you can order it from a place in Canada at:


Never bought any from Canada and the only plastic stock I own is that 243 SPS I mentioned which I used it on with great success. Of note... after I accurized the Tikka 300 wm, I was having trouble with flinging one round out of the group off to the left a small amount. (I shoot left handed. The corps suggested I change from being a right handed shooter to a left handed shooter.) What brought the occasional flyer back into the group was holding very firm forearm pressure and this is how I shoot now... old school. I shoot better now than when I was in the corps and I was a rifle expert back then. I don't believe in free recoil regardless of what is en vogue now or not, especially with a light rifle. Keep at it... you'll get it.
Semper Fi
Tens:cool:
 

Ryan Tockstein

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Messages
72
Location
Sandy, UT
If you find something that will do that...let me know please Ryan. JB and such will add quite a bit of weight. I don't believe you can buy his stabilizer in stores but you can order it from a place in Canada at:


Never bought any from Canada and the only plastic stock I own is that 243 SPS I mentioned which I used it on with great success. Of note... after I accurized the Tikka 300 wm, I was having trouble with flinging one round out of the group off to the left a small amount. (I shoot left handed. The corps suggested I change from being a right handed shooter to a left handed shooter.) What brought the occasional flyer back into the group was holding very firm forearm pressure and this is how I shoot now... old school. I shoot better now than when I was in the corps and I was a rifle expert back then. I don't believe in free recoil regardless of what is en vogue now or not, especially with a light rifle. Keep at it... you'll get it.
Semper Fi
Tens:cool:

Thanks for the info!!! I only shoot free recoil because that's what all the instruction I've seen online says to do. BUT... I watched some of Nathan Foster's tikka videos and he demonstrated the difference in his groups shooting free recoil versus having a very firm grip on the foreend. Firm grip groups were less than one inch and free recoil groups were 1.5 or 2 inches!! After seeing that, I decided I'm going to give the firm foreend grip method a try.
 

djfriesen

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Sep 27, 2016
Messages
204
The last target seems you found something at 57.2 and 57.8. It’s hard to say what’s causing this but you are experiencing this during load development which makes it even harder to put a finger on. You mention having issues with cheek weld so I would start there as you already know it’s a issue. I find it very frustrating not having a good eye view because your scope is too high and in my opinion it’s probably the issue as your constantly adjusting your head, neck, etc... and as you shoot longer fatigue then enters the game even more than normal. Either change to lower rings or get a cheek rest that allows you to remain consistent. I’ve experienced cheek weld issues and simply put a cheek rest/ammo pouch on my rifle which has eliminated my issue on a couple of rifles. See my pic for the cheek rest I use. It has Velcro straps that can be put inside to raise or lower the amount of height you want. It works great for me. Good luck and let us all know what you find!

View attachment 171300
Any chance you can provide a link to this product?
 

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