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Rogerflat · Silver Status Member

I was doing some gunsmithing last night on my beretta co2 pistol.

The thing had a terrible trigger pull so I took it apart to see if I could make it a little better. Never really tried this before, so I had no idea what to expect. Very interesting once I got into it. I made a number of modifications including weakening the barrel spring, filing down the sear, and weakening the triger spring. The trigger pull now is much better although I've not actually fired it yet to see if it works.

What was strange is that the entire firing mechanism is all internal. When you pull the trigger, it pushes the barrel tube forward inside the gun and compresses it against a spring. Then the sear kicks in and once it disengages then the barrel slams back into the part where the CO2 and bb are emitted.

The barrel tube spring is what was making the trigger so hard to pull. What I did was compress it with a pair of channel locks and then heated it with a flame to soften the metal and decrease the length of the spring (and the subsequent pressure). This actually worked. I was able to decrese it by a quarter inch. But I was wondering if the tension that the spring exerted served more of a purpose than causing an awful trigger pull? Does it need to be high tension so that it slams backwards into the co2 piece so it releases the proper amount of co2. Because after my modification, it won't be slamming back as hard and might cause a loss of power or some other problem.

Any suggestions to those who know about this?

AirGunEric · Site Admin

I can't keep tack of who's using what 'name' on their airguns these days. Who's making Beretta copies this week?

Rogerflat · Silver Status Member

I want to say that Colt makes it but I'm not sure offhand. I actually took apart my beeman co2 pistol too, but those guys really made it difficult to get to the trigger assembly. I tried pry one of the sears out and file it down and loosen some springs, but it didn't seem to help that much with the trigger pull.

Alstone · Moderator & Site Supporter

I think you will find that the power will go down as the release of Co2 is probably determined by the barrel hitting the valve release, and if you have weakened the spring you will get a decrease of Co2 passing the valve.

Al

Rogerflat · Silver Status Member

I figured as much. It's pretty sad that the gun was engineered so that the weight of the trigger pull is tied to how powerful the gun is. I'd rather have to slide the receiver after each shot to cock it and have a nice crisp trigger pull than have a semi auto with a hard trigger pull. But, if you buy guns that are geared towards children, that's what you get.

cliffspot · Veteran Member

....on a Crosman 357 back in '85. i followed the instructions for a Colt dbl action gun in Shooting times magazine. I reduced the spring pressure and stoned the surfaces and came out with a 8-9 lb dbl action pull and a 2 lb or less single action pull. But the power went down quite a bit as the hammer spring had to be reduced to get that smooth trigger. So I took apart the valve and reduced the spring in there. Maybe you could do the smae thing in your gun? BTW, the gun shot HARD after that!

Rogerflat · Silver Status Member

I'm not familiar with the spring in the valve, but then again I didn't really look at that part in depth. If anyone has any type of diagram they could post of that mechanism it would be of some help.I checked a schematic for a similar style co2 bb repeater pistol and the valve assembly just looked like one or two solid pieces. No springs that I could see.

Alstone · Moderator & Site Supporter

Some Co2 guns have a very weak spring behind the valve to start the closing movement agains't equal Co2 pressure, then the Co2 takes over so on most Co2 guns adjusting the sping makes no diffrence, adding weight to the hammer or increasing the hammer spring will make a diffrence.

Al

Rogerflat · Silver Status Member

In this type of co2 pistol, I'm not sure what would be considered the "hammer". I have one that does have a conventional hammer on the back of the gun, but this one is all internal.