I have a few Crosman MSP AirRifles as many already know. I have modified all of them with very good results. Though I do have a few questions for those that know more than I on the Crosman MSP's:What is the longest pump stroke of current Crosman MSP's that use the 13XX/760/66 or 2100/2200 type valve?What are the differences between the standard 13XX/760/66 valve and the Benji 39X valve? I know the 13XX/760/66 and 2100 valves.What are the limits of valve volume in what guns with out changing the pump linkage?What are the weaknesses of the Benjiman 39X AirRifles? Asking for point of information.What is the order of strength in the hammer springs of current Crosman/Benjiman MSP's?Are there any good trigger tunes that can be done for the Crosman 760/66 and/or the Crosman 2100/2200?How much work is involved in converting a Crosman 2100 into a Croamsn 2200, assuming that you can turn down the ends of the barrel to fit with out any issue?Is there any way to modify the loadfing area of the 2100/2200 to be more like that o the older 66, or the 13XX/2289?What is the TRUE power of the Benjiman 392?Could some one give me real chrony numbers for the current Crosman 2100 in its stock form (I have only had older ones).I thank all for any input. This will help me in my future choices with Crosman MSP AirRifles. Also any information that I do not know of about modding these is welcome.I hope that the information that others put forth in this thread may be of help to many.
I can answer one of your questions. The true power of my 392 after a tune by Tim at Mac1 is 26.8 FPE using 28.4 grain Korean pellets on 14 pumps. I don't shoot it often because it's a workout to get that kind of power and it makes a lot of noise.
The pump tube from a 140/1400 is the same diameter as the 13XX and 2100 but uses a different valve.... They can be converted to hold a 13XX valve, however....
The Benji 39X valve is way larger in diameter, about 0.77".... It is larger than a 22XX/Disco valve, and about 4.2 cc (0.26 CI) volume....
Valve volume and pump volume aren't really related.... a larger pump just takes fewer strokes to reach the same pressure for a given valve....
The Benji's use a brass tube, so a lower pressure limit.... and the stock linkage will fold up if you overpump.... A stronger billet linkage is available from Mac1....
Weakest to strongest hammer springs.... 22XX.... 13XX.... 2200.... Disco
No idea about your other questions....Bob
Quote from: DavidS on June 25, 2014, 11:17:54 PMI have a few Crosman MSP AirRifles as many already know. I have modified all of them with very good results. Though I do have a few questions for those that know more than I on the Crosman MSP's:What is the longest pump stroke of current Crosman MSP's that use the 13XX/760/66 or 2100/2200 type valve?What are the differences between the standard 13XX/760/66 valve and the Benji 39X valve? I know the 13XX/760/66 and 2100 valves.What are the limits of valve volume in what guns with out changing the pump linkage?What are the weaknesses of the Benjiman 39X AirRifles? Asking for point of information.What is the order of strength in the hammer springs of current Crosman/Benjiman MSP's?Are there any good trigger tunes that can be done for the Crosman 760/66 and/or the Crosman 2100/2200?How much work is involved in converting a Crosman 2100 into a Croamsn 2200, assuming that you can turn down the ends of the barrel to fit with out any issue?Is there any way to modify the loadfing area of the 2100/2200 to be more like that o the older 66, or the 13XX/2289?What is the TRUE power of the Benjiman 392?Could some one give me real chrony numbers for the current Crosman 2100 in its stock form (I have only had older ones).I thank all for any input. This will help me in my future choices with Crosman MSP AirRifles. Also any information that I do not know of about modding these is welcome.I hope that the information that others put forth in this thread may be of help to many. Currently the longest pump stroke is the 2100. The Benji is longer, but uses a larger tube as well. As to valve volume, the 2100 can be extended at the expense of stroke, simply by using a 66 or 760 check valve half, and a shorter piston. The springs are pretty much the same between the smaller pumpers, the 2100/2200/39x use the most potent, the 13xx derivatives use the lightest. I do not have a 760 spring to check. The Benji uses the same spring as the 2100. Triggers are easy to fix on the 2100, replace one spring and tweak the other, and they become nice. ( a little polish doesn't hurt either) Converting a 2100 to .22 cal is not too hard. Reworking a 2260 barrel is about the only way to get a new one though. The 2100 barrel support can be reworked with a 7/32 bit, one pass and it's a 2200 support. Opening it out to 3/8 on the barrel end will reduce the amount the barrel needs to be turned, and allow for a better seal to be created. The 2100 bolt will then need to be sleeved with your choice of material, add an O-ring at the same time for the breech seal. I am in the process of making a bolt for my 2200 in just this manner, the original just won't hold up to being PCP'd at 3k for some reason. I have resealed a Benji and the weaknesses I saw are mainly, the material gauge of the lever could be heavier as the levers are known to bend at ~ 15 pumps or so. The T-port is not easily worked over due to the soldered construction. The valve is O-ringed on both ends and there is no other seal at the T-port so the air surrounds the entire valve at the shot. (waste volume) Thank you for the volumes Bob You posted while I was still typing.
I've done 2 stage mods on 760 & 2100 triggers . See post http://www.gatewaytoairguns.org/GTA/index.php?topic=65696.msg625723#msg625723 for the 760 trigger. This post shows the trigger parts in the receiver. http://www.gatewaytoairguns.org/GTA/index.php?topic=68602.msg652611#msg652611 See post http://www.gatewaytoairguns.org/GTA/index.php?topic=59823.msg576064#msg576064 for some chrony numbers of my refurbed 2100 stock & after some mods. I thought I posted the trigger for the 2100, but I guess not. I'll do that when I get some pictures the next time I work on it. Here's the post of the 2100 converted to .22 Cal. http://www.gatewaytoairguns.org/GTA/index.php?topic=61128.msg585890#msg585890
I can give you the stock chrony numbers on the 2100 if you give me a couple days. I have 2 of them unmodified (yet). I just don't have the time because we are gearing up for July shutdown at work and I'm doing 12 hour days. Next week is shutdown and I will be off for a week with no real plans other than play with our guns and the dog we just rescued from the street. His name is Rambo.... more on him later.
I will check them side by side at consecutive pumps. I normally use the Winchester 7.9 domed pellets. I'm also waiting for EGillman to return from vacation and get started on wood replacement stocks and forearms for these so it's good you caught me now before anything at all has been done. (except for normal oiling) Again, give me a couple days to get work out of the way.You may also be interested to know, I just sent the payment for the 2240 converted to .177 I got from the classified. I plan on buying the bulk fill kit and adding a steel breech and 18" to 24" bbl. I know you like the MSP but, this should be a fun little shooter.
Quote from: Perry01 on June 25, 2014, 11:53:32 PMI can answer one of your questions. The true power of my 392 after a tune by Tim at Mac1 is 26.8 FPE using 28.4 grain Korean pellets on 14 pumps. I don't shoot it often because it's a workout to get that kind of power and it makes a lot of noise.Well thank you for that. Though I was looking more at stock power at 8 pumps before modding (I do all my own modding).
Quote from: DavidS on June 26, 2014, 08:29:27 AMQuote from: Perry01 on June 25, 2014, 11:53:32 PMI can answer one of your questions. The true power of my 392 after a tune by Tim at Mac1 is 26.8 FPE using 28.4 grain Korean pellets on 14 pumps. I don't shoot it often because it's a workout to get that kind of power and it makes a lot of noise.Well thank you for that. Though I was looking more at stock power at 8 pumps before modding (I do all my own modding).Thnk you for that.If memory serves me, stock power at 8 pumps was 15 FPE.
David,Not sure if you saww or not but AGD has the Reburbed 2100 for $34.99 today
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