Benjamin Trail Grouping Poorly

[Bryan Heimann]

My WTM will do better than 2" at ten yards just gripping and ripping with any pellet.  To put this into perspective, whn I shoot a group from 16 yards rested and another with the artillery hold, they are two distinct groups a good two inches apart.  On the other hand, if I just hold it tight I can get decent groups with fair consistency, or if  I use the artillery hold I can optimise my groups but then my POI will vary wildly from my artillery hold zero and shooting in realistic field conditions and probably gripping and ripping.   That is a good example of hold sensitivity and variation of poi based on a loose vs. a tight hold.  I can still hit a 1.5" spinner at 16 yards every time with a tight hold as long as I have good follow through.  2" at ten yards with with a trail- that's probably not from hold sensitivity.  With good follow through and even a tight hold like a PB you should do better than 2" at ten yards with just about any rifle especially after experimenting with ammo.  Just my 2 cents

[GKU]

Mines took a lot of time and $200 sent on mods to get from 10" groups @ 10 yards to inside nickel size (3/4") groups @ 50 yards. Problem I change the trigger CTD, (I read here on forum it would help, is a must have and a great upgrade I agree) and grinded bear trap linkage to clear shear pin. That voided my warranty and the gun sill shot bad, for lucky ones that got a better gun not so bad. Improve only buy about 6" groups @ 10 yards. If I knew trigger up grade didn't help that much, I would have returned it. So I mod it till I was satisfied (basically had to rebuild the gun) every weekend for 3 mouths. Was it worth it you ask? NO, still mad at Crossman ! That's what convinced me to buy a FX Revolution intend of a Mrod, and with on regrets. I feel bad for those who first start out air gunning with this problem(s) and get fustraighted and blame themselves in being a lousy shoot, and sadly quit before even starting. And never knew this forum existed............

Turns out to be the gun.

[Rex]

I listened to all the comments and am returning mine before embarking on the murky waters of a long, tedious rebuild.

[Mr.Happy]

Heck, reading all the reviews on here is making me want to return my Benji. But I wont. I got it at such a great deal that makes it worth putting some money into it and to learn how to tune. I finally installed CDT's trigger yesterday but didn't see much of an improvement on POI. My groups are still around 1.75" at 15 yards. Its still breaking in so sometime today im probably gonna pick up some goo gone and swab the barrel. Stuck a q-tip in it yesterday to find all kinds of blackness on it. Unfortunately I don't have a chrony to check on my numbers because the rifle feels like its lacking in power and the pellets wont punch through a 3/4" particle wood board. Also the cocking action feels a bit grindy. I feel like it might be the piston seal but I don't know where to start looking.
I would recommend to the OP that there is soo much to learn from making mistakes, or learn from other's mistakes. I don't know much about tuning airguns but I am very gifted by our Maker when it comes to any kinds of mechanics so Im not afraid to tackle big jobs. I ended up going the cheap route on acquiring a refurb Benji Trail to justify the amount of money Im gonna put into it to tune the rifle and learn from it to become well versed and well equipped. That way when I acquire the bigger, better, and more expensive rifles, im not fumbling around. Of the research Ive done, Benji Trails are solid rifles after some work. They may not be dead on, but its still a cheap fun rifle to plink with. Heck, cheap enough to loan to friends or family when you go out for a day of plinking/shooting. The way I see it, my Benji is not bad on accuracy. Depending on distance, the average POI is still within the kill zone. So whatever choice you end up making, make sure its what you feel is right for you.

[MonsterManiac7]

Ok velocities were in order 712, 726,730,738,726,711,728, 716.......looks like this might be an issue! What does this mean?

[donw]

Dan gave you some great advice (clean, tissue, q-tip, etc)  so no need for me to reiterate however.... my advice is to get rid of the sand bag in the rear and the soft towel in the front that you're using during your shooting sessions.  Keep the rifle solidly pulled into  your shoulder, like you're shooting one of your big game rifles, and don't let anything support the front of your rifle except your hand.  It's ok to rest the back of your hand on a solid rest but make sure that your hand is the only thing directly supporting your forearm stock.  Also, grip the rifle firmly, just as you would your big game rifle, forget the artillery hold.....use the same hold you use on your deer rifle.  With all that done now take your shots and see if you notice a difference.  I think you may indeed see a big difference. 

The last thing is the pellets,,,,  it be that you just haven't found the right pellets yet.   Try some other pellets and see what happens.  I know you ordered a sampler pack and tried them all but get some additional pellet types and try them.  I have a couple of rifles in my collection that drove me crazy until I found the right pellet,, then the rifles were a dream to hunt with.   

You've done a lot of work on your rifle so don't give up, hang in there and keep shooting.  You'll get it all sorted out. 

Jeff

^^^i agree

[Paul68]

Ok velocities were in order 712, 726,730,738,726,711,728, 716.......looks like this might be an issue! What does this mean?

Depends what pellets you tested with.

Assuming 14.3 gr CP's or CPHP's, those numbers are right in the normal range. HOWEVER, they are a bit inconsistent and have a somewhat large spread (26 fps) between high low. Nothing too major though. Looks like about normal if a smidge low for a stock Trail. I'd say its safe to rule out the piston seal.

Since this is the second gun and now it appears the powerplant is in average shape, I'll have to join in with others in suggesting its your shooting technique and not the rifles. Hold and consistency really does play a huge role in how an AG performs. For an example, I have a Ruger Air Hawk that's make a single ragged hole at 25 yards when using the classic artillery hold. If I try setting the gun on a bag, table, or any kind of rest, the groups open up to an inch with flyers going even further. My Jet on the other hand works poorly with the artillery hold and prefers to be held very tightly at the trigger. The trick with both guns was practicing with different holds, finding what worked, then using those holds consistently.

[MonsterManiac7]

The grouping is now 1" vertical line at best. Always a vertical group though. I cannot tell you guys how long I have spent trying different holds and I assure you that is not the problem....in both guns combined I have taken probably over 2000 shots, thats plenty of time for me to tinker with hold and nothing has worked.

[jessered]

tldr whole thread so sorry if this has been brought up.

Are you using a scope and are you sure it is not the scope itself?

My Gamo whisper was shooting 1-1/2 to 2" groups at 10 yards even after I learned the artillery hold until it finally blew the scope out. Changed the scope to a Centerpoint wally world special and I get 1/4" groups.

[MonsterManiac7]

I have tried 3 scopes....im shipping it back tomorrow and selling the brand new gun

[TooJung2Die]

Jon, I feel your pain. I'm not new to air guns but I'm new to this tuning hobby. Back in the day when I bought my RWS 45 you would send your gun and scope back to RWS and they would "Laserize" it. You got back a tack driver.

Now I'm playing with tuning a Crosman Fury and a Remington Summit. With the stock taken off these two guns are practically indistinguishable. All the parts are interchangeable. For the life of me I can't get the Fury to shoot consistently. I ruined two scopes on it while trying. I bought an inexpensive 4x32 Winchester scope from Walmart and mounted it on the Summit. The Winchester scope promised to be able to withstand the shock from spring piston air rifles. I can shoot dime sized groups at 20 yards using the artillery hold. Group size could probably be even better but that is the extent of my skill with the stock trigger.

Once I was sure the Summit was shooting well I switched the Winchester scope to the Fury. Accuracy was 1" groups at 20 yards. But that success was very short lived. Now I'm afraid I have three bad scopes. The Fury is back to being a unpredictable scattergun. At least I can return the scope.

What I have learned is some of these guns seem to be scope killers. The light plastic stock of the Fury is probably a big factor. I think if you can find a scope that will survive on your Benjamin Trail you will find happiness. For a long time I thought it had to be me. After weeks of experimentation and thousands of pellets I found out otherwise.

Jon

[MonsterManiac7]

Gun is in the mail now! i just DONT have the time or desire to get this gun shooting good. I figured when I bought it way back when it would be a simple lethal gun that would take a couple of hours to setup, boy was I wrong!

[GKU]

The grouping is now 1" vertical line at best. Always a vertical group though. I cannot tell you guys how long I have spent trying different holds and I assure you that is not the problem....in both guns combined I have taken probably over 2000 shots, thats plenty of time for me to tinker with hold and nothing has worked.

It sound like a lockup issue. Did you try Bryan's 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.  Start closing it firm and that will tighten up immediately.  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 receiver will literally wear in to place.  Pretty much, the surface is galling.  Eventually they will wear in to match perfectly."

[MonsterManiac7]

The grouping is now 1" vertical line at best. Always a vertical group though. I cannot tell you guys how long I have spent trying different holds and I assure you that is not the problem....in both guns combined I have taken probably over 2000 shots, thats plenty of time for me to tinker with hold and nothing has worked.

It sound like a lockup issue. Did you try Bryan's 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.  Start closing it firm and that will tighten up immediately.  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 receiver will literally wear in to place.  Pretty much, the surface is galling.  Eventually they will wear in to match perfectly."

Well I don't have the gun, but yes I did this and it seemed consistent. I EVEN opened and closed the action probably around a 1000 times the night before I returned it. After all that wear(I mean their was shavings of metal around) it grouped exactly the same.

[GKU]

Sounds like you had a really bad one.....

[robtmc]

Sounds like you had a really bad one.....

After following this thread for days, I think you are right.

I'll not post my saga of fun and games for a while, if ever, until satisfied that all has settled down. 

At this point I am waiting to see if the consistency is there for some pellet testing with the Straight Shooters variety set.  Still using Sports Authority Crosman pointed stuff until then, which has grouped well on occasion.  Have finally gotten the rifle to group fairly well, though not as tight as I would like at 20 meters.

Working on a good shooting setup so my shooting mistakes are separable from mechanical before reporting as you have done.  My short form opinion is it is indeed crappy barrels and inconsistent lockup.

[GKU]

Mines like JSB 8.4 grains the best, next would be Crosman Hunter 7.4 grains (Sports Authority Crosman pointed). It real hates everything else I've tried, and sadly my favorite Polymags too.
I would think JSB 15.89 grain in .22 would be comparable to the 8.4 grain in .177.

Check out this post also  http://www.gatewaytoairguns.org/GTA/index.php?topic=47785.msg450605#msg450605  if you're interested in a slight mod, if you haven't done so already.

The manufacturing of this gun is so inconsistent, that everyone's experience with it varies also. Witch make it that much harder to help someone.
http://tedsholdover.com/video/reviews/benjamin_trail_np/

[robtmc]

Mine is a .22, so a different set of pellets to try.

I spent a lot of time with the breech, and may describe the work and results later.  I suspect that even a half-hearted attempt at fitting the breech to the rifle by the factory would eliminate most of the issues.  That and prep the chamber entrance.  Mine was just chopped off.