Night Force/Sightron comparison question

[gmorganal]

I have been using a NF 12x42x56 BR scope on my 600-yard rifle. I have had some concerns about double-grouping with this scope, meaning you shoot three in a hole at 100 yards, no change is observed in the flags, and you shoot two more in the same condition that turn a group in the 1s into a 3 or 4-tenths group. THis happened Thursday at my range, so I switched to a brand-new 10x50x60 Sightron with a dot recticle. The image appeared to me to be clearer with the Sightron. I was messing around with bullet depth seating at the same time, so I can't honestly say the the Sightron was or wasn't better at holding POI or not. Once I found what appeared to be a sweet spot on the depth seating, I loaded up and moved to a 520-yard range. The first group I shot was the best this rifle has shot at this distance, and it was around 4:00 in Birmingham and some of that 1.1 inch group was probably due to the mirage. That group formed high and right of my aiming point, so I clicked down and left to center it up on the target. The next group was basically a 3/2 group with three shots with 8/10s of an inch and two shots high, making the overall group a 2.8 inch group.

My question is, can you rely on the Sightron and make reticle adjustments between your sighter shots and the official group.

The conditions these groups were shot under were what I would call almost still with a half inch to an inch of mirage.

 

[mikecr]

I can't answer the Sightron question, but suggest that there is more that can cause double grouping than a scope(you probably know).
This is where it pays to hold a 'reference' scope in the safe. That is, one you KNOW works perfectly in every regard.

I had an NXS scope cause this due to a lens bedding issue(that NF fixed quickly). But it was very hard to determine this as it was intermittant. I picked up an extra/used scope(another NXS) to prove the issue to myself, and NF didn't question it. They believed me.
With another gun that started doing this, I was able to eliminate the scope as an issue(using my reference scope), and it turned out that my firing pin setting was shifting. (watch it with a chrono)

 

[Jim See]

funny not 5 minutes ago I was out back shooting my 284, it has not been to a match yet and I am set on a load.
I shot a 15 shot string at 600. checked the target adjusted the scope to center up and then shot a five shot group.

2 shots were at the same elevation as the first 15 shot string, 1" apart. the next 3 you could cover with a quarter but they were about 2.5" higher. I have a 8x32 sightron on it. Not for long!

 

[racesnake]

I've had, until recently, a 8X32 Sightron and presently have a 10X50. Both scopes were at least equal to my NF 12X42 in regard to clarity (at a given power) and zero stability . Thse are the first Sightron scopes I have owned and I am, quite frankly, impressed with them. Maybe you should send your's back to Sightron and have them checked it out.
Dave

 

[mikecr]

racesnake, gmorganal is wondering if your Sightrons actually move POA with adjustments accurately -prior to the next shot. Or do they a physical shot or two to settle into their new POA?

I've seen this settling even with NF randomly. I now overadjust a click or two & back to counter it, and this seems to reduce it.
I've thought about mounting a small spring loaded rubber hammer(effectively) to a scope and doing some testing in this regard.

 

[gmorganal]

I have friend here in town that won our last club 520-yard competition. He uses a 10x50x60 Sightron on his BAT 6BRX. He shot a .693 group during that match and ended up agging a 1.9 inch agg. The scope obviously can work at a high level, but he told me that he prefers to hold off as opposed to adjust his scope in between the sight-in and the official targets. He told me that he hasn't had a problem with the Sightron but that he just doesn't "feel" comfortable with adjusting during a match unless it is just definitely necessary.

 

[racesnake]

I went to the range today and did some elevation checks with the 10X50 while there. Testing was performed @ 100yds. I clicked up 15Minutes from my 100yd zero in 5minute increments and shot 2 shot groups at each interval. I then clicked down in 5min increments and fired 2 more shots @ 5 minute intervals. Results: No vertical variation in groups. Distances between group centers were as follows: 5", 10", 14 7/8". Can't explain the 1/8" error @ the 15 min. interval. Measurements were made with a steel tape. Didn't have time to do windage but from past experience with the scope I'm sure it would do equally well. The rifle I used is a very accurate 6BRX - usually shoots in the .1-.2"'s.
Dave

 

[in2deep]

You can talk to lots of shooters and do alot of Googling or whatever and almost never hear of a Sightron being sent back for repair.
Odds favor looking elsewhere first.