GTA
Support Equipment For PCP/HPA/CO2 and springers ,rams => Optics, Range estimation & related subjects => Topic started by: Pellet Fun on August 11, 2015, 06:05:23 PM
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I have a Benjamin Trail NP .22 with the CenterPoint 3-9x40ao scope.
So far out of the box I cleaned the barrel using CLP-5 and cotton patches with fishing leader -- no brushes. Next time cleaning I will use a dowel as some people suggest. After cleaning I installed the GRT3 trigger and performed a crown job.
My concern has to do with the elevation and windage knob adjustments and floating the Erector Tube thereby losing a zero. The elevation is almost all the way out. The windage is about in the middle with no more adjustment left. It's tight.
It seems that I can get a zero but my groups are wandering without further adjustment. I'll get a group and then it starts a new group in a new spot.
I am using a firm base with hard pillows for a rest. It isn't sand bags but seems okay for now. I have tried the artillery hold and a firm hold with similar results.
The barrel seems to have a tight lockup regarding the side shims but there is a little droop. Not much but it's there. I will try to shim inside the back scope ring due to the droop. This may take out the slack in the elevation adjustment.
I am curious to know if the elevation and windage adjustment knobs can be removed and adjusted internally. I believe this is possible on some scopes. I haven't found anything to suggest this is possible for this scope.
I won't rule out a better scope and would appreciate suggestions. Cost is not my primary concern. A good scope for this rifle is. I can save. I generally shoot 25 yards in my backyard with this rifle but would like to shoot greater distances when going to the range.
I know this is a starter rifle and feel like it's a great learning tool. I want to maximize this thing before an upgrade. Plus I like it. I am surprised by the power. My backstop is pressure treated pine and it hits hard. I will get a metal trap soon to reclaim the lead.
Thanks for any input.
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My concern has to do with the elevation and windage knob adjustments and floating the Erector Tube thereby losing a zero. The elevation is almost all the way out. The windage is about in the middle with no more adjustment left. It's tight.
It seems that I can get a zero but my groups are wandering without further adjustment. I'll get a group and then it starts a new group in a new spot.
I just had to deal with a similar problem. A good scope on a known good shooting gun. On this rifle, the elevation knob needed to be almost all the way up. It would shoot almost hole in hole at 30-35 yards. Then after bouncing around the cart the POI would be an inch off. Would have to rezero constantly. Finally decided not be lazy and shimmed the rear of the scope. Re-zeroed. Bounced the butt off the ground a few times hard. No change in POI. :D
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Looks like scope ring shims are in my future. I still wonder if the elevation could use an internal shim in order to take up some slack? I wouldn't want to break the nitrogen seal and potentially introduce oxygen (moisture) but I can't help but wonder if it can be done. I'm not worried about a warranty. I'm too curious.
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Looks like scope ring shims are in my future. I still wonder if the elevation could use an internal shim in order to take up some slack? I wouldn't want to break the nitrogen seal and potentially introduce oxygen (moisture) but I can't help but wonder if it can be done. I'm not worried about a warranty. I'm too curious.
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My concern has to do with the elevation and windage knob adjustments and floating the Erector Tube thereby losing a zero. The elevation is almost all the way out. The windage is about in the middle with no more adjustment left. It's tight.
It seems that I can get a zero but my groups are wandering without further adjustment. I'll get a group and then it starts a new group in a new spot.
I just had to deal with a similar problem. A good scope on a known good shooting gun. On this rifle, the elevation knob needed to be almost all the way up. It would shoot almost hole in hole at 30-35 yards. Then after bouncing around the cart the POI would be an inch off. Would have to rezero constantly. Finally decided not be lazy and shimmed the rear of the scope. Re-zeroed. Bounced the butt off the ground a few times hard. No change in POI. :D
And..... The problem came back. Turns out it wasn't the turrents. It's the AO. I zeroed the rifle at 30 yards, turned the AO and shot again. POI shift of 1-1.5 inch. Time to find out how the warranty works on this scope. S
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hat kind of mount are you using Gary?
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A few things - first, the packaged CP scopes are bottom line quality.
Second - if the turrets are all the way, one way or the other, the erector will not be stable.
Third - get a better scope, CP 4-16X40 at Wally for $65, Hawke Sport 3-9X40 at around the same price. Then read up on scope centering and barrel bending. There are several current threads on both of these.
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hat kind of mount are you using Gary?
Weaver style mounts and I believe the rings are one inch. The rings came with the package.
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A few things - first, the packaged CP scopes are bottom line quality.
Second - if the turrets are all the way, one way or the other, the erector will not be stable.
Third - get a better scope, CP 4-16X40 at Wally for $65, Hawke Sport 3-9X40 at around the same price. Then read up on scope centering and barrel bending. There are several current threads on both of these.
I appreciate the suggestion for a better scope. I will not mess around with this scope anymore. I learned a lot due to the problems with using the "package scope". Plus I'll read up on the centering and bending.
Thx folks
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My concern has to do with the elevation and windage knob adjustments and floating the Erector Tube thereby losing a zero. The elevation is almost all the way out. The windage is about in the middle with no more adjustment left. It's tight.
It seems that I can get a zero but my groups are wandering without further adjustment. I'll get a group and then it starts a new group in a new spot.
I just had to deal with a similar problem. A good scope on a known good shooting gun. On this rifle, the elevation knob needed to be almost all the way up. It would shoot almost hole in hole at 30-35 yards. Then after bouncing around the cart the POI would be an inch off. Would have to rezero constantly. Finally decided not be lazy and shimmed the rear of the scope. Re-zeroed. Bounced the butt off the ground a few times hard. No change in POI. :D
And..... The problem came back. Turns out it wasn't the turrents. It's the AO. I zeroed the rifle at 30 yards, turned the AO and shot again. POI shift of 1-1.5 inch. Time to find out how the warranty works on this scope. S
I read up on the AO issue that you point out. I can see why scopes are such a big topic. I have always used iron sights and have always been intimidated by scopes (until now).
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A few things - first, the packaged CP scopes are bottom line quality.
Second - if the turrets are all the way, one way or the other, the erector will not be stable.
Third - get a better scope, CP 4-16X40 at Wally for $65, Hawke Sport 3-9X40 at around the same price. Then read up on scope centering and barrel bending. There are several current threads on both of these.
I appreciate the suggestion for a better scope. I will not mess around with this scope anymore. I learned a lot due to the problems with using the "package scope". Plus I'll read up on the centering and bending.
Thx folks
I have 2 of those same scopes, one on a Benjamin LE/NPS and the other WAS on my NP XL1100, only changed it because I saw the 4-16X40 Centerpoint for the bargain price of $49.97 on clearance at Walmart. Both scopes have performed perfectly and that's with 100's of rounds fired. I'm not saying it's NOT a scope problem but I have a hunch that if you shim the REAR scope mount with the thickness of a business card or so and rezero you'll be ok--after you get it broken in. I had to shim both of mine like that to get the elevation centered to start with. Good luck!
BTW, if you feel you still want to upgrade I might be interested in buying yours.
Ed
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Ed, I'm going to check out WallMart for any current sales and go from there. If I jump on a better offering I will get back on possible sale of my used CP and thank you.
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The scope is $5 cheaper on-line. If you tell them, they will price match. Five bucks is five bucks!! The Benjamin 7.9 HP, 750 count tin is under 7 dollars!
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Ed, I'm going to check out WallMart for any current sales and go from there. If I jump on a better offering I will get back on possible sale of my used CP and thank you.
Best of luck scope shopping! You may find a Centerpoint 4-16X40 in a local Walmart but they are out of stock on their website as well as Amazon & Crosman websites. They had a couple at one close to me a week or so ago on clearance for $49.97 and I couldn't pass up the deal. Should have bought both of them! Went back a day later to do just that but the other one was gone. I posted about my find and a couple of others here were able to find one at that price. I've not used any but I understand UTG/Leapers scopes are very good for reasonable prices.
You should really try shimming that rear mount! If the elevation adjustment is near it's max your groups will look like shotgun patterns and remain low because the spring is binding up inside. "Barrel droop" is a very common phenomena with break barrel air guns & it's solved by shimming the rear mount or using a droop compensating mount. When you shim the rear you recover the elevation adjustment you need to get on target & get closer to the middle of the scope's adjustment range. Just sayin'.....
Ed
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A few things - first, the packaged CP scopes are bottom line quality.
Second - if the turrets are all the way, one way or the other, the erector will not be stable.
Third - get a better scope, CP 4-16X40 at Wally for $65, Hawke Sport 3-9X40 at around the same price. Then read up on scope centering and barrel bending. There are several current threads on both of these.
+1
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I realized I needed to shim the scope but since I wanted a better one anyway I went to Walmart and picked up the CenterPoint 4-16x 40. I went ahead and made a shim from an aluminum soda can and one complete wrap of electrical tape. I was very careful with installation not wanting to bend a brand new scope from over tightening the rings but believe me it's tight now and hasn't moved.
All went well with the install and it took very little to adjust both the elevation and windage. I put about 100 rounds through the rifle and can now say I am having tight groups and have been focusing on the artillery hold with my thumb aligned straight ahead. It made a difference from using the thumb hole.
I probably could get a satisfactory group with the old scope had I shimmed it? Maybe I will put it back on this gun one day and use the better one on a new toy?
I really like this inexpensive rifle. It's making me think too. Air gunning is a neat sport. One last thing, I am going to make a camera mount in order to make some videos - just for fun. It looks straight forward and I don't care about the weight shooting from a bench, plus it will come off easily.
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Glad you got it straightened out Pellet Fun.
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I realized I needed to shim the scope but since I wanted a better one anyway I went to Walmart and picked up the CenterPoint 4-16x 40. I went ahead and made a shim from an aluminum soda can and one complete wrap of electrical tape. I was very careful with installation not wanting to bend a brand new scope from over tightening the rings but believe me it's tight now and hasn't moved.
All went well with the install and it took very little to adjust both the elevation and windage. I put about 100 rounds through the rifle and can now say I am having tight groups and have been focusing on the artillery hold with my thumb aligned straight ahead. It made a difference from using the thumb hole.
I probably could get a satisfactory group with the old scope had I shimmed it? Maybe I will put it back on this gun one day and use the better one on a new toy?
I really like this inexpensive rifle. It's making me think too. Air gunning is a neat sport. One last thing, I am going to make a camera mount in order to make some videos - just for fun. It looks straight forward and I don't care about the weight shooting from a bench, plus it will come off easily.
Glad it worked out for you. Nahh, that cheapie 3-9X40 scope that came with the rifle is pure junk, don't bother trying to shim it. Just send it to me and I'll dispose of it properly. ;)
Ed