GTA
Airguns by Make and Model => Benjamin Airguns => Topic started by: Perry on July 07, 2010, 03:10:53 AM
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I posted this article on the old GTA today but since the new forum is up and running now, I decided to post it here as well....
The barrel of my Benjamin Trail NP is bent so I need to decide weather to send the gun back to Crosman for an exchange or to wait till Feb 2011 for a replacement barrel.
Meanwhile I bought a Titan GP .22 from Wallmart. On first glance it appears to be the same gun as the Trail NP but without the weaver rail, shrouded barrel and sling mounts. After I brought it home I cleaned the barrel with GooGone and shot it over the chrony. After the first 10 shots it settled down to average around 710 FPS with 14.92 grain FTT pellets. It continued to diesel so I ordered a couple JM teslas seals and tore it down. I decided to break down the Trail NP at the same time to compare the two rifles. One of the pictures is a side by side picture of the two guns without stocks:
The seal on the Titan had more nicks than any other seal I've seen.
The tubes have the same inside diameter and the pistons are identical as well as the gas rams. The gas rams each have the date of manufacture stamped on them. They also have the same trigger group. The only difference is that the Titan has a spacer (seen in picture) behind the gas ram. It gave it a little more pre-load. The overall build quality of the Benji Trail seems to be better than the Crosman Titan.
They both weigh the same and are evenly balanced. The Trail NP shoots the same FTT 14.92 pellets 775 FPS for 20 FPE. So I assumed the gas ram on the Trail NP is more powerful. I decided to switch the gas ram from the Trail NP to the Titan to see if it would be able to shoot in the 20 FPE range as well. I did the usual deburr and lube to the new Titan, it had lots of Chinese mystery oil in it. It cocks easier with moly on the metal parts and I'm sure the seal will last longer with silicone grease lining the compression tube. I installed a new GRT III trigger and put the new Tesla seal on the piston and put the Titan back together using the gas ram from the Trail NP.
After a few shots to make sure everything was working okay, I shot it over the chrony. The numbers improved to 730 FPS average but still nothing like the 775 FPS the Trail NP was getting. I'm sure it will get a little better after the seal breaks in. Tomorrow I will mount a scope and see how accurate it is.
I wonder why the big difference in power? 17.5 FPE versus 20 FPE for a gun with the same power plant. I wonder if the spacer behind the gas ram on the Titan could affect the power that much?
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Very interesting Perry.
How thick is the shim ?
I hope this doesn't mean that Crosman is going to be doing the Gamo "parts swap two-step" to come up with a new gun !!!!
Paul
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Paul, the shim is about the size and thickness of a nickel. Can adding a shim that size effect the guns power?
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Interesting,
So since you have shot both, is the Benjamin quieter than the titan?
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Perry if the measurements are identical between the titan and the trail np then take the shim out and see if the FPS picks up afterward. It would be pretty cool to find out that if we bought a titan we can unlock more power by simply removing a spacer.
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looking at that pic the end caps ( whatever they are called) do not look the same lenght, are they? might be why the shim was used.
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Rabbit you're right, looks like the smaller ID towards the milled out area (for a sheer pin?) is shorter than the other. I would imagine by looking at the bluing that the bottom one is for the Benji and the top is the cheaply made Crosman version.
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I'm pretty sure that the size of the rear blocks are the same and the spacer goes into the rear block followed by the gas ram so it doesn't really matter. The spacer adds more preload. I figured more preload equals more power but I'm still at a loss as to why the Trail NP has more power with the same internals.
Rabbitguy, the Trail NP is a little quieter.
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Paul, the shim is about the size and thickness of a nickel. Can adding a shim that size effect the guns power?
Perry,
A shim the thickness of a nickle may put enough pre-load on the ram to up the FPS a noticable amount, but by how much, it would need to be tested.
I tried shimming the Air Venturi ram in my Whisper, but it turns out that ram, in that gun, was just about bottomed out without shimming. I didn't know that and almost bent the cocking arm after adding just one standard 1/4 inch steel washer as a shim. Tried thinner shims and it still wanted to bottom-out the ram before it could cock.
Paul.
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Rabbit you're right, looks like the smaller ID towards the milled out area (for a sheer pin?) is shorter than the other. I would imagine by looking at the bluing that the bottom one is for the Benji and the top is the cheaply made Crosman version.
Famine,
Just the oposite - the Benji Trail is the upper one with the weaver scope mount welded to the reciever. All the Trails have that.
Paul
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I would have thought for sure the bottom was for the Benji, shows how much of a noob I truly am. lol
Is the one that is higher (benji one) just older and seen more wear and tear? I would have thought that the benji would have had nicer bluing than the crosman parts.
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Guys, allot depends on how true the tube is. Even a new seal will not seal or contour itself properly in the tube. Chinese made guns seem to be the worst. But again maybe the Turkis guns are worse but I am not gonna tune or by any of them to find out...:)
And shimming the pistons may cause the gun not to cock. Like on some models of springer's, there is not enough room to put a stainless thrust washer under the spring. That will cause coil bind and you will never get the gun to cock. So just a thickness of a washer is all the tolerance you have..
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I would have thought for sure the bottom was for the Benji, shows how much of a noob I truly am. lol
Is the one that is higher (benji one) just older and seen more wear and tear? I would have thought that the benji would have had nicer bluing than the crosman parts.
Famine,
I think what you see as wear is actually the, "Benjamin Trail NP" logo. It's screened on the side of the reciever in very dull gold letters.
The bluing on my Trail XL is very nice. The stock fit is very good with no stock contact wear marks anywhere on the reciever.
Paul
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So, Perry whats the biggest difference between the two guns? That you can see. As far as the inside. I'm aware of the physical differences. Scope Mount, Sling rings etc.
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Yellowstone, the internals are the same in the Titan and the Trail NP. The biggest difference is the Trail NP shoots about 50 FPS faster than the Titan and is also a liitle quieter. I am going to mount a 3-9X40 scope on it today and test for accuracy.
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Well i have one and after reading this i think i will try removing the shim, seems to me it would give a longer fireing stroke, i will let you know sometime this weekend. thanks david
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Well i have one and after reading this i think i will try removing the shim, seems to me it would give a longer fireing stroke, i will let you know sometime this weekend. thanks david
It'll be interesting see what your results are.
Normally, as with springs, increasing the preload of a gas ram by adding a shim should raise the pressure ..... and I assume, also raise the resulting velocities. Since the compression tube and piston seem to be the same for both guns, but the Titan is shimmed, I'm guessing that the Titan probably has a gas ram that is factory charged to a lower pressure than the one in the Trail NP ???
Without equipment to measure the ram pressure, Perry's swapping rams will be the next best test.
Paul.
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Swapping the gas ram did not improve the velocity of the Titan.
I mounted a new scope and rings on the gun yesterday and shot a couple hundred pellets through it and I have to say I'm rather disappointed with the accuracy of the Titan.
I tried several different pellets and tried different holds and was not able to get good groupings at all. Maybe I got a lemon; I will give it another day of testing before sending it back.
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My Titan shoots rather well my girl Friend can hold a much better group then I can she pretty much right on with it. Mine seems to like CPUM
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i picked up a titan today, i'm over all impressed with it. it groups rather well, if i do my part. on occasion i'm getting a flier or 2, but i think its me, and possibly it being a brand new scope. i am going to take it out this weekend and put a tin of CPHP's through it, and break it in good. i will also clean the barrel good with goo gone tonight to prepare it. but the accuracy does seem to vary a bit... even though the barrel does look nice and cleanly rifled.
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Maybe the barrel makes the difference in velocity. Perhaps the pellets fit tighter / seal better in the Benji barrel giving more FPS???
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Maybe that's the answer toolmaker; I don't know. I ended up returning the gun to Wallmart and now I'm waiting for my Trail NP to arrive.
I'll report on it after it gets here.
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i would like to know the answer of this as well.... i'm goign to try to put in my order with PA tomorrow, for a trail XL
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Hi,
I went to the Crosman website and downloaded the parts manuals for the Trail XL and the ELS22
The ELS:
http://www.crosman.com/pdf/manuals/ELS77-ELS22%20NITRO%20EVP.pdf (http://www.crosman.com/pdf/manuals/ELS77-ELS22%20NITRO%20EVP.pdf)
The Trail XL:
http://www.crosman.com/pdf/manuals/Trail%20XL%20EVP.pdf (http://www.crosman.com/pdf/manuals/Trail%20XL%20EVP.pdf)
Crosman probably used their "detuned" piston (see ELS22 diagram, item 12, having part number 8RNP-13) to reduce the rearward travel of the cocked piston.
Then assuming Crosman designed the standard Trail and low velocity Titan GP rifle to have the starting load on the nitro compression spring, Crosman would have to place a spacer behind the nitro compression spring, which the GP has.
Perry, did the nitro piston compression springs from the GP and XL have the same model numbers? What were they?
Or did you measure the lengths of the piston body and rod section and compare the lengths?
When you swapped XL nitro compression spring into the GP, did you kept the spacer in the GP rifle as well? I suspect you did in order for the velocity to be unaffected by the swap.
I suspect Crosman simply just used the detuned piston to reduce the GP power and velocity. What would be very telling would be to swap the front piston section (see ELS22 diagram item 12).
Based on my suspicion, I believe that if you swapped the detuned GP piston with the XL piston, and then possibly removing the spacer if needed to cock, I suspect the GP would have the XL's power.
Perry, if you no longer have the GP and you still have the XL, perhaps you and I could measure our pistons to see if there is a difference in the distance from the front seal to the trigger catch point.
BrianW :-)
P.S. I have the Walmart Benjamin Titan GP 22
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There is no way a XL ram will fit in a Crosman Titan nor a Benji NP. ..Not unless you have a special shoe horn I am not aware of...:)
Crosman has changed vendors at least twice for the gas rams since they first introduced the NP and XL series nitro guns.
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Regardless of the vendor that supplies a given part, the manufacturer has an engineering drawing that a part must conform with.
From a manufacturer's point of view, it is essential the parts conform to their specs in order to maintain the assembly of current production lines and to supply repair parts.
That being said, if you have precise measurements of the ram and body that shows the 2 parts cannot fit together, I would then understand your comment. I would greatly apreciate any dimensions that anyone has.
Still, I feel it is very likely the GP and NP have a minor interchanged parts that makes the difference in velocity.
The main parts are interchangable (see the part numbers in the Part Manuals) with model identifying prefixes. If the barrel, trigger, and air-piston are interchangable then the piston rams should interchange as well.
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Then assuming Crosman designed the standard Trail and low velocity Titan GP rifle to have the starting load on the nitro compression spring, Crosman would have to place a spacer behind the nitro compression spring, which the GP has.
Does this mean the Titan GP "low-velocity" and the regular benjamin trail are the same rifle except for the shrouded barrel and lack of a spacer on the piston? What's the benefit from Crosmans perspcetive to sell a Benjamin Titan GP, Crosman Titan GP, Crosman Titan GP "low-velocity" and a Benjamin Trail? Seems like it all would just increase prices for consumers, if they are all the same rifle with one difference.
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It somewhat makes sense that crossman would sell the low velocity GP version through Walmart where the prices are lower. That way it supports vendors selling the normal crossman line from unfair competition since most other vendors don't have Walmart's bully power to demand the lowest price unit.
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Ho
Those with multiple gas ram or gas springs should check the pressure to compress the gas springs.
My experience is that some have leaked and some come from Crosman with different pressures.
The pressure to compress is easily checked.
I did mine with a car jack. I raised my car and let it down on a gas spring on top of a bathroom scale.
I have 6 crosman gas springs for the Titans. The best pressure I got was 139 pounds.
If yours does not give this kind of force then you should replace the gas spring.
Call Crosman and get a new spring.
I would like to hear from those that check their gas springs.,
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Gonna dust this tread off as it appears no real conclusion was reached
determining whether the gas rams will "actually" interchange between the Titan and Trail XL platforms