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Posted: 3/2/2008 7:15:48 PM EDT
| I have a Bushmaster and I clean and lube the thing after each shooting trip. After cleaning and lubing her, she is smooth as silk and feels great. After about 30 rounds the bolt will start to 'dry out' and after 100 rounds the bolt will not move in and out of the bolt carrier without really having to crank on it. I shoot some bf clp and it fixes it for the next 30-60 round session but it is rather annoying that I have to lube the bolt this frequently. Is this normal? If not what can I do to fix it? Any help would be appreciated and sorry for the long post. |
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First off, Welcome to the site!!! With just the carrier (bolt off of it) work the carrier in the upper receiver (shotgunned open). Confirm that the gas tube is entering the key correctly (read doesn't need to be realigned), and the the key is not having it's way with the upper track too much (read key a little wide for the upper slot). Also, you what ammo are you shooting. Wolf ammo is not the best choice to break a Bushmaster rifle in. |
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Thank you very much. I worked the carrier in the upper receiver and it seems okay. The gas tube is entering the key correctly. You can feel the gas tube touching the carrier key but it isn't a forced entry. Is this too close? Same goes for the upper track. I'm also shooting 55g American Eagle and 55g Black Hills Blue Box. I've tried Wolf Ammo once and I will never use it again. What do you guys think the problem is? Would a misaligned gas system cause this? Thanks in advance. |
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. What do you mean by "really crank on it". Does the BCG cycle, ie. upon firing, cam out of battery, travel rearward, cock the hammer, travel forward, strip and load a round, cam back into battery without using the manual assist? Or is it stalling out somewhere in the cycle? When you clean and lube up the BCG do you check to make sure the carbon build-up in the bottom of the carrier recess for the boat tail is cleaned out until no carbon remaining on visual inspection? Do you assure that the three gas vent ports out the side of the carrier in the vicinity of the ejection port are clear and clean, ie. can you see the bolt tail and piston rings clearing those ports? Do you hose down all the bolt and bolt carrier surfaces including gas piston on the bolt and carrier cylinder until dripping wet then just dab up the drips after cleaning and before reassembly? When the bolt carrier group gets hot from high rate firing and a hot gas stream, the lights of the BF CLP will evaporate and give the appearance of dry, but there is still lubrication there. What is your rate of fire? |
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Hello CCW. Yes the BCW does cycle fully without stalling. I have not yet had to use my forward assist. When I clean and lube up I really clean up. There is no carbon build up anywhere that I can visually see. The bottom of the carrier recess if cleaned out very well with Q Tips as well as the vent ports. I usually spray down the bolt and bolt carrier with CLP and let the excess drip off before I reassemble. I just got back from the range and the best way I can describe it is that the action between the bolt and bolt carrier is "gritty" and I only shot 65 rounds today! My rate of fire is extremely slow! I normally pound out a round every 5 seconds (the range I go to won't allow rapid fire). However, even when I do pound out rounds in a quick manner the results are still the same. Thank you for helping guys! |
| thank you for the quick reply! just checked it and they look fine. I was searching the forums to see if anyone else might have had this problem and I saw a post about someone having a rough time with their bolt and carrier after installing the Mcfarland 1 piece gas rings...I just installed those rings in my gun. Would these rings cause this kind of problem? |
| oops. To answer your question about the buffer tube, spring, ect yes they are gtg. In order to slowly eliminate the possibilities I slowly disassembled my gun piece by piece and retested for the grittyness. It is the contact between the bolt and bolt carrier. I'd remove the firing pin and felt it...still gritty. Removed the cam pin...still gritty. Removed the bolt from the bolt carrier and wiped down JUST THE BOLT and reinserted...still gritty. But when I wiped down the inside of the bolt carrier it smoothed out. I'm totally lost. |
Bingo! The Mcfarland, may exert more radial pressure on the carrier gas cylinder. Put three new stock split rings back on. Make sure the cavity on the bolt for the rings is thoroughly cleaned before installing the rings. I did not know folks were still using Mcfarlands. |
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