I need some ideas. Strange groups

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Mike6158, Nov 26, 2009.

  1. Mike6158

    Mike6158 Well-Known Member

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    Strange to me anyway.

    I've been shooting my VTR (.308) for the last few days. It's a new rifle and it's been through a decent break in process (posted elsewhere).

    Today was "check loads" day so I set up at the 100 yard range. I loaded 4 groups of 6 at .010, .050, .090, and .130 off of the lands. The .090 group was better than the others. .130 was so bad that I didn't even shoot the last 3. With that noted I moved over to the 200 yard range and shot some "foulers" that I had also loaded.

    The "foulers" were loaded with 42.2 grains of H-335. Sierra says that's 2,700 fps but I didn't take my chrony so with the short barrel on the VTR I doubt if I had that kind of velocity. The 150 gr Sierra ProHunters (#2130) were loaded .010 off of the lands.

    I cleaned the barrel after doing the test shots so I started on the 200 yard range with a clean barrel. The first round was 3.75" low and 2.25" left :cool:

    2,3,4, and 5 were dead on and 1/2" - 1" of each other

    6 was dead center and 3-1/2" right
    7 was 1.5" up and 2" left

    All in all a very strange group (to me)

    Obviously I like 4 of them :D

    Couple of things to note:

    My scope is high. My cheek does not rest on the stock like I'm used to. The stock is an HS Precision that is very similar to the Sendero SF II stock. Scope rings are medium height. The rail is a 20 moa tac rail. Scope is a Leupold Mark IV 4.5-14 x 40mm LR/T. After I get back from a deer hunt next week I'll change the scope to a Mark IV 6.5-20 x 50mm LR/T (the old scope is going to find a new home on an AR10 in .308) which is why the rings are a little high.

    I find that it is not intuitive to shoot with the scope so high. I'm used to anchoring my cheek on the stock and then adjusting as needed to see through the scope. My cheek or any other part of my face does not touch the stock. Is this normal? I "sort of" think that the 3 fliers were shooter related but I am also wondering if the first one was because it was more or less a cold / clean barrel shot and the other two fliers were because I shot fairly quickly and the barrel was pretty warm by the time I got to them.

    Any ideas?
     
  2. bryceh12321

    bryceh12321 Well-Known Member

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    Well first off I've heard some pretty harsh reviews about the VTR. I was actually looking at one myself until I read those.

    But still, theres no way it could be that bad unless somebody wasn't doing their job at the factory. I'd say I'm about 95% sure this is due to the guy pulling the trigger (no offense; I've had my fair share of terrible shots :rolleyes:)

    A cold/heated barrel like you mentioned could have some affect, but 3-4"? I'm no expert, but that seems like a big difference due to a cold/hot barrel unless the manufacturer sent you a nice tasty lemon.

    Post back if you get that thing figured out, will you?
     

  3. Mike6158

    Mike6158 Well-Known Member

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    No offense taken. I don't mind putting it out there and hearing what I'm already thinking. One thing about the VTR- the factory stock is pathetic...

    I figured that since I had 4 very tightly grouped rounds that I did something but ?? I don't know what. At 100 yards the groups from all 24 rounds while not great, were usable for hunting. Around an inch except for the .130 off the lands. Those were bad. The weird thing about the 200 yard fliers was that they formed a nearly perfect triangle. I'm pretty sure I didn't flinch as the gun has very little recoil.

    I'm going back out today. 20 rounds all loaded the same way.

    The more I shoot the VTR the better it gets BUT I've got a 20 year old 700 BDL in .270 with an older 3-9 Leupold that gives me sub-moa groups even at 200 yards. Always has.

    On the upside I can always send it to someone, have a new barrel put on it, bed it, and tune the action up :D At least Remington still makes a decent action. Or I ould just sell it. Or I could use it for a deer slayer and not worry about driving tacks.
     
  4. MontanaRifleman

    MontanaRifleman Well-Known Member

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    A rifle will almost always need some fouling shots to settle down after a cleaning - shot 1. I'm surpised it didn't 2 or 3 but giving it a good break-in may be why. Shots 6 and 7 might be from the barrel heating up, especially with the triangular shape of the barrel. Seems to me it might lead to uneven stresses with temp change.

    You should have a lot better idea than any of us reading this on the trigger puller. Did you feel any differnt about the trigger pulls 6 and 7 than the previous 4? It would take a significant difference to be that far off if you have a good stable rest to shoot from.

    My suspicion is the rilfe and possibly heating from firng. Let your bore cool between each shot to ambient temp and see what happens.

    Mark
     
  5. peashooter

    peashooter Well-Known Member

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    I had A Rem VTR and could not get it to shoot any bullet in a 2" group @ 100 yards. I finally switched the powder to Varget and tried the 168 gr. SMK seated so long it will not fit the magazine. This combo will shoot very well even we have now switched to Nosler AB and BT because they open up better on groundhogs. These too are seated long enough they do not fit the magazine. The VTR ia basically a single shot, but that is all it takes with a well placed shot. Good luck with your VTR.

    Peashooter
     
  6. Mike6158

    Mike6158 Well-Known Member

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    I actually feel pretty good about trigger pull. The rest was good. Sight picture was steady. I shot again this evening after making a scope change (more on that below) and once I was sighted in things went very well. I believe that what you posted is the likely scenario after today. I need to be sure to do a couple of sight in shots at the lease next week before I go to the stand and hold off on cleaning until after I shoot my deer. <--- hows that for confidence :D

    I did something similar today. I loaded 10 rounds .010 off of the lands and took the powder charge down to what is supposed to be 2700 fps. The results were very good.

    The more I thought about it the more I felt that I needed different (lower) scope rings. My Sendero is still a work in progress so i decided to take the scope off of it and mount it to the VTR. Both guns have tac rails and rings so it didn't surprise me when I checked it at 25 yards (before going to the 100 yard and 200 yard side) it was dead on. It needed adjustment at 100 yards and fine tuned at 200 yards but all in all the change didn't take long to shoot in. The difference in magnification (14x max vs 20x max on the new one) AND the position of my head on the stock with the lower rings, I think, helped. When I went to the 200 yard range I was hitting 1" low and 1" left. I made one adjustment and fired two shots. Center and 1/2" high / 1/2" left :D Time to box it up and play with the AR15's.

    I have two home-brew AR's with 18" Shilen match barrels. One of them inherited the VTR scope with the high rings. It was a perfect fit. Originally both AR's had Leupold AR scopes. Not bad scopes really... I just wanted a little more power for the 200 yard range. My son (working in Iraq. He's a Field Service rep for BAE. Fixes MRAPS... great truck) will inherit the other AR scope. Once it was sighted in I put 7 rounds inside of a 2" circle, some touching, at 200 yards. That'll do for deer or hog hunting. The other AR does really well (7 rounds inside a 1" circle) at 100 yards but I didn't get a chance to shoot it at 200 yards. I'm going back tomorrow so we'll see.

    I picked up (2) more powders (RE-17 and TAC) I think I'll load 10 each with those powders to go with the rounds I already loaded with H335. I need to bone up on 1 in 12 twist barrels, bullet weight, etc...
     
    Last edited: Nov 27, 2009
  7. gunuserc15

    gunuserc15 Member

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    I know this is a little bit on the too little, too late side but your intial problem could have been caused from paralax. I used to shoot a HK91 that had a claw mounted scope on it, which was WAY too high. If I didn't have my head exactly in the same postion every time I shot my groups would be much larger than normal. It wasn't a "precision" weapon to start with but I could still get 2" out of it when I was precise in my head position. Sometimes I would zing a round out that was 5" from where I was aiming. When I asked an ol' wise shooter what the heck was happening he explained it to me in the following way.

    Modern day scopes are built to exacting tolerances. If one tiny thing is off in the scope like it wasn't mounted correctly and the tube is bent by millimeters, or a lense is slightly out of alignment, then your bullets won't go where you think you are putting them. If you think of your eye as a lense that works with the lenses of the scope then the same is true when it comes to alignment of your eye and your perception of where you are aiming.

    I hope this helps a little. Good luck with your new lead delivery systems!
     
  8. Mike6158

    Mike6158 Well-Known Member

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    I think parallax had something to do with it. I also think the trigger had something to do with it (as well as the trigger-er). I checked the pull and it was almost 7#??? on a rifle that is supposed to come set from the factory at 3#. I think something was sticking. I finally got it set at 3# but I decided to order a Jewell trigger for it. Talk about something really making a difference. I set it at 1# 5oz (matches my 7 mag) and now "trigger control" becomes a matter of making my self pull the trigger and not tap it. I also think that the loads had something to do with it. Once all of the variables lined up the gun started shooting very nicely.

    Anyway- the rifle finally settled down enough for me to make a nice 285 shot on a deer. I should mention that I wasn't expecting to shoot any farther than 100 yards but this years hunt was a little tough so I had to take what I could get. I made the shot prior to changing the trigger. I haven't been to the range with the VTR since I changed the trigger. Just my brother-in-laws place to play.