Scope issue on a Gauntlet 1st gen

[otis1016]

Evening everyone,

I recently bought a first generation Gauntlet in .25 from a classified ad here. It’s a very clean gun in good condition and I’m happy with it. I added a Crossfire 4-12 40 and am having a problem new to me. With air pressure well into the green and shooting at 10 meters it was hitting about 5” low. Five shots later I had added all the elevation adjustment it had and was still an inch and a bit low. I went to 15 meters and it was still low by about the same amount. It’s grouping quite nicely at about 1/2” but still low. The rings are the same height and I’m not seeing any odd elevation angles in the mount setup. I tried a different scope a few weeks ago and elevation was fine so changing scopes is the only variable. Same pellets, same air pressure, about 10 rounds fired each time. No wind, heat and humidity ridiculous as usual. I’m planning on shimming up the scope in the rear ring between .025 and .050 and seeing if it hits center while allowing me to remove a substantial part of the elevation adjustment. I figure if I run completely out of any adjustment, even if it is hitting properly something is wrong. Any other suggestions? Thanks.

Rick H

 

[Keene]

Is barrel droop even a thing with PCPs?

 

[WorriedMan]

Otis,
I've owned the same type of gun since February 2021, not aware of this problem being common to the Gauntlet. Had to shim a scope to correct a similar problem but was on a Crosman F4. Adjustable scope rings are often suggested by members, as well. Also, don't forget to try JSB 33.95 grain Exact King Heavy Diablos. WM

 

[nervoustrig]

If I'm picking up everything correctly, you changed the scope and the rings (same height rings, but different rings nonetheless). So the discrepancy could indeed be the scope but check the rings carefully for anything that could be elevating the front of the scope, among them:

1. A recoil pin partially sticking out of the bottom of your front ring.
2. Clamping plate upside down on one ring or the other. Most rings have reversible clamping plates that accommodate either 3/8" or 11mm dovetails. One tooth has a shallower angle than the other. If one plate is flipped relative to the other, the scope may angle up or down...which could either be a problem or an advantage depending on how it ends up. If unsure, try swapping the front and rear rings to see if the symptom changes.

Also if you have touched anything relating to the barrel or shroud since the previous scope was installed, that could be a factor. Even if it has been untouched, it wouldn't be a bad idea to check the grub screw(s) holding the barrel in the receiver to be sure they are snug. Many airguns, especially those in the value segment, have a pretty sloppy fit between the barrel tenon and receiver. If the barrel becomes loose enough, groups will suffer but there is an earlier point at which the barrel will simply sag.

 

[otis1016]

Thanks everyone, I thought through all this last night. I couldn’t find any of my thin sheet metal this morning and if you saw a picture of my shop you’d know why. I cut four small pieces of 220 grit stick on sand paper and put that on the rear scope ring with the sticky side up. Got everything thing straight and snug. The recoil pin is retracted so no pressure there. Scope rings are properly oriented. No loose screws that I can find. I took it out before lunch and pumped up to the same air pressure, used the same pellets, same target and distance exactly, same temp and humidity. First shot was 1.5” high, exactly what I was hoping to see. Four shots later I had taken out a turn and a quarter of elevation and it was perfect. All the mounting screws stayed snug and all the other screws on the rifle are tight so I think this problem is solved. Until I shoot it again anyway. I have a match at CMP in about 10 days to prep for and a rim fire match the week after that so lots of practice to do. Not really a bad thing.

Rick H.

 

[WorriedMan]

Otis,
Congratulations, same results I had. A piece of an aluminum can works well, too. Enjoy owning my Gauntlet but the dovetail scope mounting, clunky bolt action and questionable magazine design really speaks to an older PCP technology. Can't argue with the performance, though. FYI, Hajimoto Productions offers great videos and upgrade parts. Happy Shooting, WM

 

[Old-School]

As WM mentioned, a strip of soda can aluminum works well for shimming. "Back in the day" folks used to use strips of 35mm photo negative for the same purpose. You have to be careful not to damage the scope tube when tightening the rings when using shims. There are purpose-built adjustable rings for this purpose that prevent stressing the scope tube, but for an inexpensive scope, it may not be worth it.