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Posted: 2/12/2008 6:54:24 AM EDT
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Howdy, this is my first time , hope i can relate here what my problem is with my RRA varmint 14 6" rifle, I posted this in the troubleshooting forum but hardly anyone in there right now, hopefully one of you can help. I noticed that after sighting in that it drastically shifts poi, sometimes by as much as 8 inches, this is high and low, not so much left to right. I have used 2 different scopes and mounts to make sure it wasnt a problem with my scope. I have noticed a little play in between tha upper and lower, more so than my Colt HBar. It shoots the best with Hornady TAP 75 grainers but i use the cheapo fmj 55 grains for yotes. I have had 2 instances with the gun being off at close range and far range. The close range i was hitting the ground in front of the yote by a foot, the long range i had to have been shooting over the yote by at least 8 inches. What gives ? Is this the most finicky gun or what ? I understand that i cant hold the gun exactly as i did on the bench, and have shot it standing up with great results, just when a few days go by and we hunt, its shooting off. Does any one have an idea whats going on ? Has this ever happened to you ? Skiebuster |
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What is your sight-in distance? What are your group sizes with, say 55 gr remington ammo? Does the POI shift with iron sights as well? So you're saying that despite acceptable group sizes (I assume) at sight in, your point of impact (at what distance?) shifts by up to 8 inches with the same ammo type? Point of impact will differ by up to 8 inches at 100 yards if you switch ammo types. You generally have to sight in a gun for the same type of ammo you will use in the field. |
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group size with 55 varies, some are less than 3/4, cheapo's will be under a inch. 2 different scopes and mounts and no iron sites as its the varmint model. When i have shot different ammo types for hunting i have reset my scope onthe bench then on to hunting. Seems like after i site it in then a week later while hunting it has shifted, with the same ammo i sited it in with. hinking.gif and i set my groups to shoot a inch or so high soi will be on at 200 yards. |
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Well time doesn't have anything to do with it. If you use 55 grain ammo and shoot from 50-200 yards, a 50 yard sight in will give you what you want (as you say about an inch high at 100yds). I'd sight in the gun at the bench then knock, pull, thump, shake and otherwise try to get the scope to move. Your POI shouldn't shift at all. Outside temperature has some effect on the POI, but this isn't going to make a 5 MOA difference. If the rifle groups within 1 MOA one day and the POI is off by 8 inches the next week your problem has gotta be either a loose scope, bad scope, or loose barrel nut. |
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Globe, Shadow, Scope on it now is a Bushnell elite 3-9x50, had a luepold varix 3 before that, both did the same, millet anglocs on the upper reciever, tight, i checked that. Scope is nice and tight, inside the reticules aint moving, i dont see how you could site it in to group good if that was the case. Coud you feel the slop if the barrel nut was loose ? |
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Well scope quality sounds fine and if your mounts are solid then they are solid. I doubt you would be able to feel a wobble in the barrel unless the nut were loose. Only way to check is to get a wrench and if you can tighten it applying less than 30 ft lbs of force then the nut is loose. I kinda doubt this is the problem. I would just go to the range and experiment with the thing. Shoot a 10 shot group, manhandle the barrel, scope, etc a bit and shoot some more groups. Anything short of dropping the gun on the scope should not change POI. I highly doubt you would be able to shoot 1 MOA with a loose barrel. |
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I have to wonder if you are not understanding the arc of the trajectory. Sight in for 50 yds and you will be very close at 200 yds. The bullet will start at 2.6" under the line of sight, and cross the line of sight the first time at 50 yds. This means the impact point will be very low at 5 to 10 yds. I often shoot running shots at super close range an I have to aim over the hog to get a hit. The bullet will go over the line of sight by about 1.5"or 2" at 100 yds., falling back down to the line of sight at 200 yds. I don't want to insult your intelligence, but we just don't know your level of knowledge. If you understand this concept, you will be fine. I would not be suprized if you weren't seeing the height shift down if you are a new shooter. Sometimes new shooters will push down really hard on a rifle to try and hold still. Then they adjust the scope to account for this down pressure that drives the point of impact up. Then they try to shoot off hand and this bending pressure is gone and the POI drops badly. Use a moderate cheek weld pressure and don't try to grip the hell out of the rifle. I know that my rifles are always sighted in because my bench technique duplicates my contact when shooting off hand. I use light pressure on the rest so this has extremely little affect on the POI. |
+1 U must 1st harness the power of the 'Arc' my son... |
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Thats great advice for a newbie, but i have been shooting ar's for over 15 years. Ive owned 3 colts and now this ROCK. Most of my shots on yotes have been snap shots, lift, reticule hits fur and squeeze in 1 fluid motion and dead dawg down. I am going to switch scopes again, and give it 1 more round of shooting, then go back that day, shoot then the next, anything shifts or changes, its going back for further evaluation by RRA. So, i cant think why in the world would cause a gun to shift poi with 2 different scope/mounts set ups. Ihave never overheated this gun, i bought it new, only site in and shot at some yotes. |
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Update for all of you who gave me some great info, i have replaced the scope, again, and thumped 30 rounds getting it sighted in and tryinh out the Burris 3-9x40 ballistic plex to 400 yards. I will clean the barrel, fire a couple to dirty it and commence to evaluating what happens. Is it gonna shift, be off or what. I am anxious to see what happens. thanks again |
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Yeehaw ! Just wanted to let every one know my RRA was fixed via tightening up the barrel lug. It holds true now without shifting patterns after a couple weeks. Thanks to RockRiver for their great custome service and sorry for such a long time since I received it back to this post on it being fixed. I needed the long term shooting of it to see if it was in fact fixed. Bring on the yotes ! |
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