Scope Swaps

[Mistered]

Well, I got to chatting with a guy on another forum and while doing so the question of whether a Weaver base will fit on a Picatinny rail came up so I had to go pull the scope off my Handi-Rifle (with Weaver Bases) and try it on my PCC - and it works perfectly! Basically a Picatinny rail is an improvement of the Weaver style in that it has more grooves for better fore and aft adjustment.
So the first pic is the scope off the Handi-Rifle and I got to thinking I might go shoot it to see just how accurate the PCC really is but I thought the scope looks kind of big on it - so then I remembered I had an old Bushnell 40 MM on an old .22 that is really clear and so I swapped it out - looks a little better as it is not so 'bulky'.

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[JEBar]

good info .... thanks for documenting it

[Mistered]

Well, I just got back from giving it a try with LESS than stellar results!
Rested the PCC and touched off. OK about 4" high and and about 1.5" to the right.
Made scope corrections and fired again with the round only moving to the left slightly and elevation about the same so I adjusted elevation down to what was a little more than what was DOUBLE according to the 1/4" click @ 100 yard standard.
Next shot elevation good but about 1.5" to the left. Well, long story short but the remaining 20 or so rounds were all over the paper with no consistency. I am going to blame the scope as it is pretty old and did not seem to adjust properly AND I can hold 1.5" with its stock sights at 50 yards.
I am going to slap on a known, good scope and try this again and hopefully get better results or just get a new 1-4X for it.
There is simply no other reason(s) for the inconsistency I experienced.

[North Country Gal]

Sorry to hear it didn't work out for you. You're right about trying a different scope. Been there, many times, trying to get more use out of an old scope. Sometimes it works, sometimes it doesn't.

One thing to remember on picatinny versus weaver rails is that the picatinny has ever so slightly wider slots. This means that weaver ring mounts will always fit a picatinny base/rail, but the fit can be just a touch loose. Not a big deal, just be sure to properly tighten. Have done it many times.

[Mistered]

One thing to remember on picatinny versus weaver rails is that the picatinny has ever so slightly wider slots.

Yep - I noticed this - a little fore and aft movement when loose but with the scope on, rings and bases tightened it shouldn't be an issue.

Yea I can't help to think the scope is the problem as just Friday I shot Wingnut's Long Ranger and BBS (both with scopes) and did well.

[wingnut]

Just FYI- When mounting rings on the picatinny or Weaver base/rail, ensure the whosever rings are seated to the front of their respective slot. Its a very repeatable spot and controls for any possible recoil movement.

Good luck!

[Mistered]

When mounting rings on the picatinny or Weaver base, ensure the whosever rings are seated to the front of their respective slot.

Got it! I already did this actually and for now this is all 'experimental'.
I think I need to simply find a good 1-4X scope with the proper mounts and I'll be good!

[Mistered]

Well, more poor results.
I swapped the scope on the PCC with a Leupold to try it again and got similar results. After zeroing the scope I had a couple 'reasonable' shots and then no consistency and shots all over the paper - and this is well rested on a bench.
Ok so I pick up my Henry BBB .357 and, after having to re-zero it due to a front sight swap I shoot the attached six shot group at 50 yards with 'open irons' (Receiver peep W/blade front) .
I don't get it. I have NEVER had this much of a problem shooting a rifle with a scope - the wild card is I shoot the PCC very well with the stock sights - even getting a couple 1.5" rested groups at 50 yards.
Any thoughts or ideas as to a reason for this ?
I am very reluctant to buy a new 1-4 X scope for it now - which is what I really want to do.

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[JEBar]

Sherlock is credited with saying that "Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth." .... as a play on words, it sounds like you've eliminated the causes to the point where about all that's left is something with the mounting of the scopes ..

[North Country Gal]

One other possibility is parallax. Leupold rifle scopes are factory focused to be parallax free at 150 yards and you are shooting at 50 yards. Unless you place your eye in the exact same spot behind the scope for every shot, you will get some POI shifts due to parallax. Next time at the range, rest the gun on the bag and line up the crosshair on a small bullseye or dot at 25 yards and 50 yards. Make sure the gun doesn't move. Then move your head left and right and see if the crosshair drifts off the center of the bull to the right and left, too. If so, you are getting some error due to parallax. Not saying this is the culprit, but it may be contributing to the problem.

Red dots are almost universally parallax set for 50 yards, so that's one way to eliminate the parallax issue. (Contrary to what some claim, red dots are not parallax free at all ranges.)

[Mistered]

Another 'wild card' with this is the Leupold I was using was recently on a .223 rifle and shooting cloverleaf groups at 50 yards.

I am thinking (reluctantly) it is in fact the scope mounts shifting as the problem.

[North Country Gal]

Sure hope you get it figured out. These kind of things truly are what I call shooting headaches. Oh, I don't mind having to do a tweak, now and then, but when a stubborn problem with one gun cuts into my shooting time with my favorite guns, I tend to lose patience, fast. Best of luck to you.

[Mistered]

but when a stubborn problem with one gun cuts into my shooting time with my favorite guns, I tend to lose patience, fast.

Yes - I understand and I am getting there fast with this issue!
I have never had this much trouble with a scope on ANY rifle I have ever owned.
I am hoping it is the mount issue IE the Weaver on a rail debacle.
A friend thinks he has a set of 1" Picatinny rail mounts I am going to borrow to try this out one more time...

[Yornoc3]

Many years ago I had a similar problem after mounting a new scope on a Win. Model 100 .284. After shooting the better part of a box of ammo, I finally figured out that the scope BASE had worked loose. The rings and scope were fine, but that slight looseness of the base flung shots all over the target. It was barely detectable by feel, though.

[Mistered]

OK - the Leupold is BACK on the rifle it came off of - for a 'test run' Friday afternoon!

[Mistered]

Well, with the scope rings Wingnut loaned me I put the scope back on and got BETTER results - but still some inconsistency.
The attached target shows two 5 shot groups I shot this morning. The circled shots are one set of five aiming (rested) on the center of the dot, and the uncircled shots are a 2nd set of five aiming at the bottom of the dot at the top of the black vertical line.
As you can see a fairly tight group of three, then a couple flyers - with similar results on the others.
Both were shot without any scope adjustments as I was just wanting to see group results.
I am going to swap the Leupold with a nearly new Nikon I have and see if anything changes.

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[North Country Gal]

Admire your patience. Yeah, scopes can go bad. Pretty rare on the good stuff, but it has happened to me. Only to check is do a scope swap. Best of luck.