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quote:
Originally posted by fritz:
5/13/18 -- As I suspected from a couple prior sessions, the 2-10X scope I purchased in December for my 16" barrel AR-15 won't hold zero and has tracking issues. Crap. From one session to another, zero can change 3-4 MOA. Between tall targets, dialing elevation & windage to max and back again, I experienced a 5 MOA downward shift after roughly 100 rounds in 3-round groups.

5/14/18 -- I wasn't ready to send the scope back to the factory. So I put my NF 2.5-10x on the upper. Initially this combo shot a little better. Then I started dialing elevation a lot, in combination of getting the barrel pretty warm. Dagnabbit, the wandering zero resurfaced. I noticed that the gas block seems to be moving (rotating) in relation to the opening in the 12 o'clock portion of the rail that allows clearance for the gas block. When the barrel was pretty warm, the gas block touched the rail. With the barrel totally cold after being the safe a couple days, the gas block no longer touches the rail.

The problem may have been with the upper, not the scopes. I should be able to confirm over the weekend.

After discussing the issues with my preferred 'smith, he took this 16" Wilson Combat upper back to the shop and gave it a careful inspection. His analysis:
- The barrel nut was fairly tight, but not completely so. My 'smith torqued it down to spec and stated there shouldn't be issues going forward. He said the 'smith who replaced the barrel may not be all that familiar with Wilson ARs.
- There's very little clearance between Wilson's TRIM rail and the gas block. My 'smith did a little milling to open up the clearance, as he suspects bipod pressure and heat from shooting makes the limited clearance a bit too limited.
- With the barrel nut now tight, the handguard shouldn't rotate relative to the gas glock.

I hoped to try the tweaked upper last weekend, while sighting in at the Raton 2-gun match, but ran out of time on the sight-in evening.

The goal for the weekend is to chrono my primary ammo types, find a good zero, perform tall target tests to confirm that optics are good, and see how the upper holds vertical at 400-500 yards.
 
Posts: 5461 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
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Picture of Voshterkoff
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I have an Origin action on preorder and have started looking at barrels, boy it looks easy to change out with an action and barrel wrench. I don't have much time shooting longer range, and I wonder if I should get a .223 bolt head and start with a .223 barrel. You can get Hornady American Gunner 6.5cm for 80 cents a round, so I'm not sure the economics are there for practice ammo. What do you guys think?
 
Posts: 8150 | Location: Woodinville, WA | Registered: March 30, 2004Reply With QuoteReport This Post
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quote:
Originally posted by Voshterkoff:
I have an Origin action on preorder and have started looking at barrels, boy it looks easy to change out with an action and barrel wrench. I don't have much time shooting longer range, and I wonder if I should get a .223 bolt head and start with a .223 barrel. You can get Hornady American Gunner 6.5cm for 80 cents a round, so I'm not sure the economics are there for practice ammo. What do you guys think?

I'm not familiar with the Origin action. Offgrid has many thousands of rounds on his Bighorn actions -- he may be able to help you. I can state that offgrid's Bighorns shoot really well and they cycle very smoothly.

I am in the slow process of building a 223 precision rifle, as a training option for my larger caliber rifles. Quality 223 ammo can be found for less than 6.5 ammo. Furthermore, a good 223 match round flies a long ways with good accuracy. The downside to 223 bullets is that they show noticeably more wind drift than their 6.5mm counterparts.
 
Posts: 5461 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
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quote:
Originally posted by fritz:
The goal for the weekend is to chrono my primary ammo types, find a good zero, perform tall target tests to confirm that optics are good, and see how the upper holds vertical at 400-500 yards.

Somehow, I don't have 100% success rate with goals.

I'm pretty comfy that the tweaked 16" Wilson upper is now put together correctly. Although I had only limited time with with AR this weekend, I didn't experience its prior issues. No movement of the gas block relative to the rail. No contact between gas block and rail. Accuracy was more consistent across a limited number match-grade ammo lines. But I still need to confirm accuracy across all my match-grade ammo options.

Before the 'smith tightened the barrel nut, I experienced a number of groups with very little vertical dispersion, but with noticeable horizontal variation. I attributed the horizontal to high & variable winds, but it may have been due to the harmonics of gas block contact. 100-yard groups now appear more concentric. Winds were unpleasant while shooting, so I didn't stretch out to longer distances. Testing a limited number of ammo options for group size and muzzle velocity was enough for the day.

One of my original concerns with this upper was the optic -- a Vortex PST Gen II 2-10x ffp. Initially, I was concerned that wonkiness in accuracy and POI was due to the scope. I'm glad I didn't blame the scope from the start of this journey. But I think I have found one issue with the scope.

First, the good news on the Vortex 2-10x.
- Glass is really clear.
- Parallax function is great.
- Reticle is useful and OK -- but I like the MOA reticle from Nightforce better
- Zero stop function is relatively easy to set
- Turret feel is decent.
- It's one of the few FFP 2-10x optics on the market. Burris is one other.
- Turret elevation tracks with reticle elevation. i.e. either holding or dialing elevation works....within reasonable values....

I think I can live with the one downside of this scope. When I spin the elevation turret all the way to the top, then back to zero, then back to the top, then back to zero -- the zero elevation changes by 1 to 2 MOA. This shouldn't happen with a properly designed scope, but it does with this one. So....I just won't dial up 65-70-ish MOA in elevation anymore and bang up against its maximum value anymore. Which is more than 2 revolutions on the elevation turret -- 25 MOA per rev. I doubt I will ever use more than rotation on the turret anyway, so it's just something to remember. When I kept dialing/holding under 32 MOA, tracking was accurate and repeatable.

Nightforce may one day distribute a 2-10x (-ish) ffp scope -- possibly in their NSX line, but could be SHV or ATACR. One NF rep told me 2-10x ffp ain't happnin', but another rep had that look..... Until then, I hope my Vortex scope continues to play nicely with my Wilson 16" upper.
 
Posts: 5461 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
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I shot my 18" barrel Wilson AR-15 in the Nightforce precision tactical 2-gun match last month. I shot the Wilson with stunning accuracy for the first day, but I just didn't seem myself on the second day. I shot the AR like dog-doo on a stage which required somewhat wobbly spools for support. I figured it was my technique, but I shot lights out from the spools with the precision bolt action rifle, after switching from the AR.

On the next stage, the direct thread suppressor become slightly loose -- causing accuracy to totally suck until I tightened the can in mid-stage. Gotta love heat resistant can covers.

But I still wasn't as accurate as I expected on the next stage.....hmmm

When I cleaned the AR I felt a slight constriction with patches early in the bore. And more carbon on the patches than normal. I shot the Wilson the following weekend briefly and accuracy was really bad. As in match ammo shooting worse than ball ammo. I began to wonder if the barrel was toast.

So I put a number of Slip Carbon Killer patches down the bore, even leaving them in the beginning of the bore for a few hours. More patches, then copper and plastic brushes. The constriction went away, as did carbon fouling on patches.

I shot the 18" Wilson again today. For whatever reason, I had to re-zero. I shot the rifle's favorite round -- Hornady 75 grain HPBT match. Initial 3-round groups to zero were printing at about .5" at 100 yards. A good sign, for sure. To confirm zero I shot a 5-round group of .61" at 100 yards, with all the variation being horizontal. Woohoo! Given that I was experiencing gusty winds from my 3 o'clock while shooting the group, wind drift variation could have added .1" or .2" to the group's size. Serious woohoo!

The barrel is still good. When it eventually does crap out, I will replace it with a Krieger or Bartlein.

In other words, I've experienced my first carbon ring in a AR-15 and learned how badly it can screw up accuracy. I suspect the stages where I had to hose close-ish paper targets with cheap FMJ ammo contributed to excessive carbon fouling. Lesson learned, and hopefully will be remembered.
 
Posts: 5461 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
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I shot my first competition last weekend in the 600 yard F-Open class. it was a small-ish club event where all 24 participants shot, spotted hits (scored) and pulled targets. It was a great learning experience. In some ways it was a lot easier than I imagined and in others, a lot harder than I imagined. it is easy to shoot a 9, harder to shoot a 10 and surprisingly difficult to shoot an X. Wind was dead calm in the morning but it did get gusty by the last round. I brought way too much gear, dressed completely wrong in long pants and long sleeves and used ammo out of my reload boxes in a very inefficient way. I only brought my small tripod to use with my spotting scope necessitating laying prone for 20 minutes spotting for another shooter. That caused extra fatigue in my shoulders. Won’t make that mistake again. My aggregate score was 574 - 11X. I did shoot one 8.

Here is a quick analysis of shots:
2% were > 1.5 MOA but < 2 (8 ring)
37% were > 1 but < 1.5 (9 ring)
43% were < 1 but > .5 (10 ring)
18% < .5 MOA ( X ring)

I made the decision to shoot the match 6 days before the event. I took a few hours off of work to go verify loads still worked as I couldn’t shoot suppressed. All of my load development is done suppressed and until the match it is the only way I shoot. I shot my Tikka T3X TAC A1 in 6.5 Creedmoor with a Harris bipod and rear bag. This was also the same weekend we took our oldest son to his new college. Preparing for the match was a real grind due to the short time to prepare, having to verify/reset zero w/o the suppressor and diminished sleep due to travel.

One funny occurrence: I was calm, relaxed and ready to shoot when it became my turn. I spotted first and shot in the second round. As soon as I got down into prone and behind the gun I realized this was a real competition and I didn’t want to screw up. My heart began to pound and the first sighter shots were timed between big heartbeats. I did eventually calm down and was fine in subsequent rounds.

All in all a very fun day and lots of points of learning.

Henryrifle
 
Posts: 481 | Location: Atlanta | Registered: November 11, 2009Reply With QuoteReport This Post
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