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New m4 update


cmscoltm4

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The newer ones have definitely been improved in many ways. After talking to the tech guys at Umarex, I purchased a new bolt spring and firing pin. Firing pin seems to strike harder, and bolt spring is much stiffer than the old one. Works really well when it's backed all the way out. I'm modifying the old firing pin to hit even harder, and strike a bigger area of the rim. Haven't finished the "prototype" yet but it looks promising. They said the barrel (chamber) has been improved also. That will probably be my next improvement. Been told the new ones will even shoot REMINGTON! That would be great since a buddy of mine GAVE me two 500 round boxes of them! They won't even chamber in my old barrel.

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Hay wobblinwheel the first time i feild stripped it i noticed that the screw for the bolt speed adjustment was 3 1/2 turns in from flush from the factory. It fires mini mags and blazers perfectly so I am hesitant to change the setting. like I said this gun runs great ! Lovin it ! Thanks for the info :)

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cmscoltm4, it would be interesting to find someone with some Remington "Golden Bullet" bulk ammo you could try. They won't shoot in ANY (older) Colt that I have heard about. I'm really curious if they would shoot in your rifle. Wouldn't recommend you buy them though, as they have an unusually large bullet diameter. My brother is machining-down the pilot on a .22 cal. chamber reamer so it will fit the "match" barrel (smaller bore dia.) on the Colt. This "finishing reamer" is the same size as a Ruger 10/22 chamber, which will shoot just about anything. I don't suspect this would affect the gun's accuracy, as the bore on the Colt is smaller and has a more rapid twist than most American rifles. In other words, I think you are lucky to have gotten a newer rifle!

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Ya wobblinwheel this gun runs perfect so far .I actully started with an ISSC mk22, what a heap that was .The store that I bought it from let me exchange it for the colt m4 carbine . I don't now if I ever want to shoot the remingtons they are a pretty dirty round.I really like the CCI mini mags and the blazers .I would like to try the new winchester m-22 rounds to see how they stack up. Thanks cmsm4colt

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Just installed my newly re-designed firing pin. A friend of mine welded a bead over the chisel-pointed end of the pin and extended the hammer-end of the pin. After custom-filing the longer pin as to eliminate the inertia action of the pin (the hammer actually now "drives" the pin into the rim, eliminating the need for a pointed firing pin), I have rapid-fired 60 rounds of Winchester M22's and over 200 rounds of Remington Golden Bullet bulk (yep, that's what I said) and NO failures! I gathered up all the brass and verified that each shell had a nice dent in it, about TWICE the size as it was before. Now I just have to keep an eye on each end of the pin to make sure they're not being "peened" by the impact. Not sure how hard the welded ends actually are. Anybody know a good way to harden the ends without making them brittle? The performance seems promising so far, as these bullets were quite problematic before the change! I am hoping to eventually create a more "tolerant" rifle from one that was once "finicky".

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I had some much clearer pics, but they wouldn't upload because they were too "big". I hope you can get the gist of the larger size and depth of strikes on the rim. These were fired in an EXTREMELY dirty rifle that started to sound like dragging a brick on concrete when I worked the bolt! Still no misfires. Seems the firing pin has surely reduced "light strikes" to nearly "0". If I only had access to correct steel, and machining capabilities, I could improve it even more.

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Well, I finally got the "pilot" on my .22 chamber-reamer turned-down so it would fit the bore on the Colt. The reamer is designed to finish the chamber to the same specs as most "American" semi-auto's. Seems to be the EXACT dimension as a Ruger 10/22. (which will shoot just about anything). the results have been VERY GOOD so far. The rifle will chamber and fire EVERYTHING that I had trouble with before. I have found the biggest failure-to-fire issues involved bullets that would "stick" in the chamber and cause light-strikes. These problems seem to be eliminated. Remington

golden bullet, CCI Velocitors & Subsonics, Blazers, all seem to work fine now! Also, I can detect NO change in accuracy. I'm beginning to really like my "I can shoot any kind of "junk" rifle!!

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The tool I'm referring to is a .22 caliber chamber "finishing reamer" for semi-auto pistol & rifle barrels. The "pilot" is the part of the reamer that "guides" the reamer straight into the chamber, kinda like a drill bit. It appears the chambers on the earlier Colt barrels were more like European "match" chambers, which have a tighter taper to them than standard "American" semi-auto .22's, which are looser to accommodate rapid-loading of a wider range of ammo. The Colt barrels also have a smaller bore diameter and a more rapid twist than most American rifles (which is a good thing), hence the need to turn-down the pilot. Since I have reamed the chamber, all ammo I've tried now chambers easily, without "sticking". Unfortunately, I feel the "positive" features of this barrel are potentially negated by the possibility of irregular "tensioning" of the flash suppressor, each time it's loosened or removed.  This is why I almost never loosen it unless it's absolutely necessary. Heat can also affect the tension on the barrel due to expansion, which also affects accuracy, but at least now my rifle goes BANG more often now than it used to!

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