Benjamin Trail Grouping Poorly

[Bryan Heimann]

Yes.  Same advice.  Cock it and close it softly, then break the barrel while it's cocked.  Then close it good and firm, and break the barrel.  If it gives more resistance when slapped, it is definitely being inconsistent.  Starty closing it firm and that will tighten up immediatey.  As it breaks in, it will wear in better and better and groups will get tighter and tighter.  The face of the breech and the face where it contacts the reciever will literally wear in to place.  Prety much, the surface is galling.  Eventually they will wear in to match perfectly.  The good news is that it makes a good tight seal there, lol.

[Hanabata808]

Much appreciated!  I'll try that this weekend! 

[GKU]

Had that problem(s) to, I change minds to a 4-16x56 leapers and had improvement, the other problems I had found is in the play it has when I closed the breack barrel there is a very small play, causing about a .oo7" movement at the barrel tip (the thickness of a postcard). I found this play by conecting a lazer to the barrel of the gun on the shroud and zeroed to the cross hair in the scope to the lasers dot and seen it move up and down and left and right as I shot. I tighten the pivot screw and tried to close it more consistently it seems to be better now. If the shots go a little left or right it can be adjusted by closing it in a slightly in a angle in the oposite direction. Moves the pellet as much as .5" at 25 yards for my gun. My groups at 30 yards is now about .75" inside of a quarter. Better but not great.

[GKU]

The guns recoil is so hard on the scopes I have, it move the internal tube housing around, causing POI to move as much as 1/4" in all directions @ 30 yards. Adding this error to all the other problems. In spite of all the work and money and valuable time I put into this gun it's still to this date the most inaccurate one in my collection of airguns. I'm even thinking of removing it for my collection........pellets are more valuable not to waste.

[robtmc]

Very enjoyable thread, lots of good thoughts to ponder.  Did check my CP 3-9 and saw no cross hair movement when jiggling the ocular, so maybe I got a good one.  I don't fiddle the magnification once I start shooting either.  That would be counter-intuitive.

I am leaning toward technique problems for my particular rifle.  I can sometimes get a ragged hole at 25 yards, then throw a few and inch or two out.  I think technique because the rifle bounces around so severely from my deliberately light hold and forearm rest.

I am going to try and hold it a bit more firmly to control the movement.  No way do the sights come back on target like my .308 with a firm hold.  of course breaking your position to re-cock starts everything over again. 

[GKU]

Very enjoyable thread, lots of good thoughts to ponder.  Did check my CP 3-9 and saw no cross hair movement when jiggling the ocular, so maybe I got a good one.  I don't fiddle the magnification once I start shooting either.  That would be counter-intuitive.

I am leaning toward technique problems for my particular rifle.  I can sometimes get a ragged hole at 25 yards, then throw a few and inch or two out.  I think technique because the rifle bounces around so severely from my deliberately light hold and forearm rest.

I am going to try and hold it a bit more firmly to control the movement.  No way do the sights come back on target like my .308 with a firm hold.  of course breaking your position to re-cock starts everything over again.

Hi Neighbors,
                 Keep checking every so often recoil may slowly kill it. It just killed my laser I had mounted on the shroud.

[Hanabata808]

I finished taking my NPXL apart and cleaning and deburring what I could. Installed washers, piston bushing kit, and new trigger.  It's noticeably smoother now, and the firing cycle is less harsh (the scope should be happy about that).  Still groups poorly, so I'm wondering if I need to clean the barrel and recrown it next.

[GKU]

I finished taking my NPXL apart and cleaning and deburring what I could. Installed washers, piston bushing kit, and new trigger.  It's noticeably smoother now, and the firing cycle is less harsh (the scope should be happy about that).  Still groups poorly, so I'm wondering if I need to clean the barrel and recrown it next.

I did the same and still poor group, I like Otis bore solvent and I use to use WD-40 also to clean barrel. I recrown mine too, to mirror finish did not improve any. Read some where if you push a Q-tip in the tip of the crown and pull out, and look closely to see if cotton fibers are left behind then recrown.

Bryans info above is also true for my benji np .177 cal experience .............

[kmiJ]

I hate to beat this dead horse anymore....poor devil...BUT...I wanted to share what I recently found ( thanks to "map8660") on my Trail's accuracy issue. I had all but run out of ideas on what to try next till he mentioned removing the breach seal spacers. I'm pretty sure with my gun that its a lockup issue so I got looking at it. If I held it to the light I could see light at the top of the breach by holding the gun sideways. So I remove both shims from under the seal and I could feel the difference instantly. Now it fits up tight to the breach, metal to metal. Less than dime size groups at ten yards, with about ANY pellet. Still need more testing to know for sure as I have been disappointed before but for now I'm happy! But for anyone who isn't thrilled with the accuracy of there Trail give this a try, doesn't cost anything and is quick and easy.

[robtmc]

I'm pretty sure with my gun that its a lockup issue so I got looking at it. If I held it to the light I could see light at the top of the breach by holding the gun sideways.

This is interesting.  In searching GTA, I found another comment opining that the breech should not be making metal-metal contact, but the seal should do all the contacting.

I have been peering at my Trail NP as it breaks in, and see evidence of m-m contact at the top left of the breech.  Which leads me to wonder how the breech lockup is designed to happen.  What is intended to be the hard stop at lockup, the breech against the receiver (compression tube) or the bottom of the breech down onto the detent?  Obviously the alive jam keeps things wedged closed either way.

The fact that the breech on mine is making most of the contact on one side bothers me for lack of symmetry, which is why I am curious how the design was meant to operate.  The breech is not a finely milled or polished surface, so no careful fitting was done. 

X-ray vision or the mechanical drawings would be nice.

[GKU]

I was convinced that their is still movement at lockup. Took out brass washers and saw the back had little dents in then from the poorly machined setting area for the washers. Had a feeling it was moving when relocking each time rocking and or rotating slightly. To get rid of this variable play I epoxy the brass washers in place using a vise to clamp fairly hard till set that I knew had parallel jaws.  I let epoxy dry overnight, light block sanded the other contact area that washer will contact till about 30% of factory machine line were gone. Reassembled added Moly to joint. Reshot and wow, now inside dime (about .5") grouping @ 100' (33yrds). Best this benji has ever shot, see a little hope it may one day do this at 50 yards ! With all the issue this gun had(s) for me if I knew the work it would take to make it shoot straight out of the box, I would have think twice about getting it. One to five problems okay, but not so hard to do for most people aren't tuners. Wish the gun was made with pride like the trigger I bought from CDT. Thanks for this forum !! I'll post again if it make 50 and what it took to do so............. Aloha all !!

[robtmc]

Took out brass washers and saw the back had little dents in then from the poorly machined setting area for the washers. Had a feeling it was moving when relocking each time rocking and or rotating slightly.

Thanks for the tip on the rough surfaces.  I have the Airguntoys washers and bushings on the way.  Once I take the barrel off, will spend a lot of time inspecting surfaces.  I sure looks like little fine machining is done there.  Tool marks everywhere.

I was looking at my old Beeman/Diana 850/6M to see how the breech was fitted, and the surfaces are like mirrors.  German machinists I guess...............

[MonsterManiac7]

Well i am done....I am sending the gun back and getting another new one. I plan to sell the brand new rifle right away.

[Paul68]

Well i am done....I am sending the gun back and getting another new one. I plan to sell the brand new rifle right away.

 I strongly advise you to get a chrony. After everything done in this thread, and the rifles still did not perform properly, the only thing left is internal issues which you will not discover without a chrony or an outright teardown. I'd also add, for anyone who is going to tear down one of these Benji's, invest in a new piston seal. They are cheap and good insurance. Even the best cleanup and lubing will not help if the seal is not doing its job properly.

[MonsterManiac7]

Dang it man....ok I will try my friends out maybe, but then I will have to spend money to get it fixed, money that i would rather spend elsewhere at this point. If anyone is interested it will be in the classifieds tonight.

[Paul68]

Naa. If you get another one and you are not interested in opening a gun up and spending money and time on tunes and mods, a chrony will let you know if you have a rifle worth working with. If the numbers are low or all over the place, you know it has issues and you can then just send it back.

[MonsterManiac7]

Dang it man....Ok so i keep saying this but I tried cleaning it tonight and its grouping about 2" at 10 yards.....my last effort will be my friends chrony.

[The Guide]

I was shooting my Trail NP .22 AW tonight with the stock CP 3x9x40AO scope on it @ 10 yards and I saw similar to what you were seeing.  I know why it was jumping though because I was trying different holds on it to see where and how the gun like being held when shot.  It like it the same way my 300 win mag likes it.  Tight to the shoulder with gentle down pressure on the scope with the stock resting on bags about 2 inches from the rear of the barrel cocking notch (about 4-5" behind the front of the stock).  If I didn't have enough down pressure it would jump and shoot high.  Too much down pressure and it would torque and shoot low and a little left (I assume due to the left hand being used for down pressure).  Just enough pressure and it would cut a dime sized hole with 5 shots.  I'm still breaking the gun in and only got 20 shots in tonight after my kids fell asleep.  I guess these air guns really are more like shooting archery than a firearm where you have to be SO consistent with your technique to get really tight groups.  I hope you can get some answers when you shoot it over the chronograph.  I need to get one since it looks like you can use them for both AG's and FA's and even archery.  Consistency is the key to precision.

Jay

[BenjiHunter]

This is the normal artillery hold.


Try to hold it like this instead, but don't grip it .
Just make sure it has side support.
Works great with my Patriot. With normal artillery hold it shoots a lot worse.

[GKU]

Artillery hold is a must for this gun is hold sensitive, but assuming he is not using this hold and using standard hold of some kind. 2" groups @ 10 yards will only improve POI by 50-70 % with the artillery hold and that's about 1" @ 10 yards witch is sill bad if you ask me. Some issue with the gun, I don't believe that he's that bad of a shooter.......