Can faulty scope causr double group?

Rifle scopes, iron sights and optics. Spotting scopes and target acquisition devices.

Can faulty scope causr double group?

Post by Kelsey Cooter » 11 Jan 2018, 9:04 pm

I've bought a 308 that belonged to a target shooter. Its bedded and free floated, and seems like its going to be awesome for me, except it gives me double groups. Iv got a brand new leupold on it. I have checked and checked and checked the scope mount screws, the action screws and iv had 4 different brand of bullet in it. Every screw has been tightened with a torque driver to the specs ruger and leupold recommend.

Could the scope have an internal problem?
Is there something else I need to check?

I have the same ruger with the same leupold scope in 300 win mag, and i shoot sub moa groups no worries
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Re: Can faulty scope causr double group?

Post by AusTac » 11 Jan 2018, 9:27 pm

Pain in the arse but i just went through a similar issue, swap the scopes, only way to isolate the fault to either the rifle or optic
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Re: Can faulty scope causr double group?

Post by deanp100 » 11 Jan 2018, 9:56 pm

What are you callng a double group?
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Re: Can faulty scope causr double group?

Post by Kelsey Cooter » 12 Jan 2018, 5:54 am

deanp100 wrote:What are you callng a double group?


If I put 10 shots on paper, some will be in 1 really tight group, and some will be in a second really tight group about 1inch lower and 2 inches to the right at 100m. Theres no rhyme nor reason as to which bullet lands in which group.
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Re: Can faulty scope causr double group?

Post by deanp100 » 12 Jan 2018, 8:04 am

Ok , that is weird. A faulty scope would generally spread them randomly . I would think if one thing moved internally but was solid enough to then hold a tight group through several shots it would stay there. I can't say I have ever seen this happen. Is it a consistent occurrence? Even heat issues from firing 10 quick shots would produce a wandering group, not a sudden jump to a different point of impact. Strange!
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Re: Can faulty scope causr double group?

Post by Wm.Traynor » 12 Jan 2018, 9:16 am

Kelsey,
I feel your pain. A scope with an adjustment mechanism that has gone haywire will group in exactly the way you describe. Check the bedding first, then if it tests out OK, send the scope to Nioa with a description of the problem.
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Re: Can faulty scope causr double group?

Post by Gwion » 12 Jan 2018, 3:18 pm

Pull the action from the stock. Check for shiny spots on your action and bedding. Look closely for small lumps or bumps or loose crud on the bedding surface. The rifle could be 'hanging up' under battery causing two distinct groups.
Also, as you suggest, it could be a dodgy scope but could also just as likely be a bit of crap in the bedding.
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Re: Can faulty scope causr double group?

Post by Strikey » 12 Jan 2018, 4:04 pm

Kelsey Cooter wrote:I've bought a 308 that belonged to a target shooter. Its bedded and free floated, and seems like its going to be awesome for me, except it gives me double groups. Iv got a brand new leupold on it. I have checked and checked and checked the scope mount screws, the action screws and iv had 4 different brand of bullet in it. Every screw has been tightened with a torque driver to the specs ruger and leupold recommend.

Could the scope have an internal problem?
Is there something else I need to check?

I have the same ruger with the same leupold scope in 300 win mag, and i shoot sub moa groups no worries



Some more info required before you start blaming the scope, what are you shooting from, a proper frontrest and rearbag on a stable bench, a bipod and rear bag or no rear bag, are you shooting prone???? What is the trigger like, heavy or does it break nicely, is the stocks length of pull suitable for you?? If the rifle has been bedded perhaps now the recommended torque specs are not working and you may need to try a different amount of torque??
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Re: Can faulty scope causr double group?

Post by Empie » 14 Jan 2018, 9:34 am

Not meaning to cast aspersions... though maybe you could get an equally experienced or better shooter to try to replicate the problem with your rifle & scope? I had a sub-conscious flinch that caused me to blink & pull (rather than squeeze) the trigger for a lot of shots. I only realised it when shooting at night & noticed the muzzle flash for only & few shots. The flinched shots were grouping to a different point than the un-flinched ones. You could also try this night shooting thing if safe where you are - if I remember correctly, the light was from a torch close to the target rather than from the shooting position - which may have allowed me to detect the muzzle flash.
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Re: Can faulty scope causr double group?

Post by Empie » 14 Jan 2018, 9:35 am

Not meaning to cast aspersions... though maybe you could get an equally experienced or better shooter to try to replicate the problem with your rifle & scope? I had a sub-conscious flinch that caused me to blink & pull (rather than squeeze) the trigger for a lot of shots. I only realised it when shooting at night & noticed the muzzle flash for only & few shots. The flinched shots were grouping to a different point than the un-flinched ones. You could also try this night shooting thing if safe where you are - if I remember correctly, the light was from a torch close to the target rather than from the shooting position - which may have allowed me to detect the muzzle flash.
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Re: Can faulty scope causr double group?

Post by Oldbloke » 14 Jan 2018, 9:47 am

Yes, check the bedding, if you can't find anything swap the scope &/or shooter to isolate the problem.
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Re: Can faulty scope causr double group?

Post by tom604 » 14 Jan 2018, 9:53 am

if you want to test the scope try this, one shot at bull,ten up and ten across one shot, twenty down one shot, twenty across one shot, twenty up,one shot then ten across and ten down should put you back on bull,if your all over the place its the scope (or you :( ) hope this helps :thumbsup:
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Re: Can faulty scope causr double group?

Post by Empie » 14 Jan 2018, 10:35 am

Not meaning to cast aspersions... though maybe you could get an equally experienced or better shooter to try to replicate the problem with your rifle & scope? I had a sub-conscious flinch that caused me to blink & pull (rather than squeeze) the trigger for a lot of shots. I only realised it when shooting at night & noticed the muzzle flash for only & few shots. The flinched shots were grouping to a different point than the un-flinched ones. You could also try this night shooting thing if safe where you are - if I remember correctly, the light was from a torch close to the target rather than from the shooting position - which may have allowed me to detect the muzzle flash.
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