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Author Topic: Is the scope the problem on my Benjamin 392  (Read 247 times))

Offline Tom1340

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Is the scope the problem on my Benjamin 392
« on: April 20, 2021, 11:25:55 PM »
Iíve had my 392 for a couple of years and have put a lot more than a thousand pellets through it.  Iíd shoot at 50 ft, with 6 pumps, and use a scope because of vision issues.  Iíve experimented with pellet samplers and am most happy with jsb domed diablos, 15.89 gr.  Iíve cleaned overspray out of the barrel. I occasionally get dime sized grouping, but more frequently I default to 2Ēgroups.  My pellets punch clean round holes in the paper target and wood backboard, with no evidence of tumbling.  Since I canít think of anything else, I am suspecting my 4x32 UTG scope, with fixed parallex of 35 yards.  I donít think parallex setting can account for this amount of inaccuracy (???).  Has anyone heard of loose internal lenses in UTG scopes that could shift during the pumping?  I hate to buy a new scope to find Iíve misdiagnosed the problem.   Any ideas appreciated.  Tom
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Offline 35 shooter

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Re: Is the scope the problem on my Benjamin 392
« Reply #1 on: April 21, 2021, 04:25:06 AM »
A 35 yd. set parallax scope shouldínt be the cause of 2Ē groups at the ranges you mentioned... but, because of the way most scope bases are made for the 39x guns, combined with the the low comb buttstock on these rifles can cause problems with getting the same cheek weld from shot to shot.

The stock on the new synthetic stock models are better suited for ease of scope use with theyíre raised combs.

Iím so used to the 39x guns and a high cheek weld with a scope now it comes natural to me, but when I first put a scope on one it gave me fits for a while.
I can do almost as well with a 35 or 50 yd. set parallax scope on one as I can with an AO scope now.

So yes, it could be your scope, but iím betting itís getting a consistent cheek weld. You will probably do much better with an AO type scope on your 39x
My face is rather long from check to chin and only a portion of the side of my chin touches the stock... otherwise my eye line is under the center of the scope if I try to use my cheek for the weld to the stock on a 39x.... not an ideal situation even with an AO scope.
With time and practice I can now shoot my 39x guns with scopes as well as any of my other air rifles that I can get a more natural cheek weld on.

The Mac1 and Baker scope bases sit lower than the air Venturi bases for me.
The Mac1 allows the use of rifle or pistol scope on the 39x.

Have you checked the crown on your bbl.?
« Last Edit: April 21, 2021, 04:37:05 AM by 35 shooter »
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Offline TerryM

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Re: Is the scope the problem on my Benjamin 392
« Reply #2 on: April 21, 2021, 09:06:53 AM »
  I bought a new 392 six years ago, curious as to how it compared to my vintage guns.  I tried every pellet in my inventory.  Two or three different scopes and a peep sight.  Cleaned the muzzle, polished the crown.  It kept throwing fliers, I was doing good to keep groups under 1 1/2" at 20 yards.  I finally listed it on ebay, inaccurate guns hold little interest for me.  I got twice what I paid for it, good old ebay!
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Offline KevinJBrown

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Re: Is the scope the problem on my Benjamin 392
« Reply #3 on: April 21, 2021, 11:33:54 AM »
Tom,

There's a lot of information missing that could help sort this out. Have you had someone else shoot this combo (do you consider them and expert)? Are you shooting off a bench or ??? Do you shoot other combos at the same range and position with better results? What accuracy are you expecting MOA, sub MOA? I shoot sub 2 MOA with a Marauder and that gets me slightly under 1" groups (basically all the time) at 50 yards. I've worked pretty hard to get the rifle to that level. I know that with other platforms I can shoot a lot better than that, but that is what the Marauder will shoot at, and I think that is pretty good for an air rifle.
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Offline North Country Gal

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Re: Is the scope the problem on my Benjamin 392
« Reply #4 on: April 21, 2021, 11:50:29 AM »
As buddy mentions, there won't be enough parallax with that setup to account for 2" groups. Some, yes, but we're talking a fraction of an inch, not 2" inches. True enough, it could still be the scope, though, if something is bad, internally. Trying another scope is generally the quickest way to eliminate this possibility, but only if you have another scope on hand.

On my pumpers, I only use 4 pumps at that kind of distance and do very well. Might be worth a try to go with fewer pumps. If nothing else, saves on work.

How's the trigger? If you're fighting a bad trigger, it's going to be tough to shoot consistent groups with these light, short guns, all the more so with stocks not user friendly for scope use.

Assuming you are shooting from a rest, the type of rest and the way you rest the gun are big factors with these classic pumpers. I use bags, front and back, again because these are fairly light guns.

« Last Edit: April 21, 2021, 11:57:39 AM by North Country Gal »
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Offline Tom1340

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Re: Is the scope the problem on my Benjamin 392
« Reply #5 on: April 21, 2021, 01:54:41 PM »
Thanks for thoughts.  I shoot from a bench, and am quite happy with the trigger pull.  I donít have any other shooters around me, so I havenít gotten a 2nd opinion.  And I donít currently have any other rifles to verify my marksmanship.  But since the bench holds the gun steady, the trigger is smooth, and the target is clear in the scope, Iím assuming my aim is not the problem.  I have read about others experience with the 392. Some, like Terry above have results like mine, while others report consistent good accuracy.  I hope I can crack the code, because I like this gun.  But an inaccurate gun wonít satisfy me. 
I havenít done anything to the crown, as I read that it is not a serious issue, but Iíll check it out. Tom
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Offline mpbby

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Re: Is the scope the problem on my Benjamin 392
« Reply #6 on: April 21, 2021, 02:00:45 PM »
Even parallax not being the reason for the 2Ē ..

Just to let you know..

Some scopes are friendly to adjust the distance for zeroing the parallax.  You may try unscrewing the front ring of the scope tube.  Then, rotating the front lens until the parallax is zeroed for closer. 
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Offline farrlarr

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Re: Is the scope the problem on my Benjamin 392
« Reply #7 on: April 21, 2021, 03:33:45 PM »
I don't see any indication that you have tried to shoot without the scope; that is probably the gold standard for determining whether the scope is at fault.  You did say that you use a scope because of vision problems so I can understand why you might not have pulled the scope so far but I think it is worth a try.  The vision problems should put you off pretty much the same way for each shot so the question would be how the shots group and whether that group size remains consistent over a series of groups.

Having others shoot would also be helpful.  Surely there is someone, whether a shooter on not, who could be convinced to help you.
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Offline North Country Gal

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Re: Is the scope the problem on my Benjamin 392
« Reply #8 on: April 21, 2021, 06:53:52 PM »
Tom, I have also had similar experiences with the Benjamin/Sheridan/Crosman 39x pumpers as far as encountering a wide range of accuracy one gun to the next. I have two 397Ps that are stunningly accurate, but also two that have been frustratingly stubborn about not getting good groups. Why, I can only guess. Hope you didn't get one of those. Don't give up, yet, though. Still some things to try on yours.
« Last Edit: April 21, 2021, 06:57:45 PM by North Country Gal »
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Offline 35 shooter

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Re: Is the scope the problem on my Benjamin 392
« Reply #9 on: April 21, 2021, 07:17:18 PM »
What scope base are you using?

Btw, Academy Sports sells the winchester 4x AO scope( made by daisy) for $30.00 if you can find them in stock.
Iíve found them to be a durable little scope and keep one around to put on if I suspect a problem with a scope I have mounted at the time.
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