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Mausingfield M5 bolt opening issue

Huskydriver

Huskydriver

Not here for a long time but here for a good time
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Apr 17, 2018
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Hoping someone can help me out here. I have a 400ish serial number M5 action with DLC and the bolt always seems to get stuck right at the top of the bolt lift when the rear cam starts to engage the bolt handle. It requires a decent smack upwards to finish taking the bolt out of battery. I have tried 4 different kinds of brass, light loads, oversized the brass slightly, lubed everything, playing with head space in and out +-.002 and nothing seems to make it open any easier. Rifle has had about 700 rounds through it now and at least 1k dry fire cycles. Has anyone else had this issue or have an idea where to start? I have reached out to ARC but thought I would try here too.

Thanks for your help
20180619_175059.jpg
 
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Does not matter,...dry fire, cycling a live fire, or hell even an empty chamber it snags a tad up top.
 
Ok, so that rules out anything to do with the firing cycle or brass fit.

There’s a detent at the top of the throw that keeps the striker assembly from being bumped into the fired position by accident. Could be that(under that small flathead screw). I’d call ARC and have them walk you through the fix.
 
Measure a sized case and a fired case on the body just forward of the rim groove.

If there is no difference, your chamber may be a little too tight. You don't need much, .001-.002 is sufficient but if they measure the same it will cause what you describe.
 
Ledzep said:
Measure a sized case and a fired case on the body just forward of the rim groove.

If there is no difference, your chamber may be a little too tight. You don't need much, .001-.002 is sufficient but if they measure the same it will cause what you describe.
Click to expand...


He says it does it on an empty chamber, even when he’s opening the bolt on an already cocked striker.
 
.70" on a fired .69 on resized. What's weird like I said is their is even a hint of resistance opening even an empty chamber not as bad as cycling freshly sized brass and nowhere near as bad extracting a fired case. Any other thoughts Zep?

Thanks
 
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Sixfivesavage said:
Does it do it with the trigger removed? What trigger is in it?
Click to expand...

I have run this with both a timney ce 2 stage and am currently using a triggertech diamond. I would have the pull the action later to test without the trigger in but my gut says that will be inconclusive since having the sear engagement out of the equation changes the feel so drastically I am not sure I follow how I would identify I potential issue unless you think its the fit of the trigger to the action.
 
Nik H said:
Call Ted on the phone....he will make it right
Click to expand...

I have emailed them if I don't hear back Mon I will try to call. I am sure he is busy getting Nucleus actions out as quickly as possible and doesn't have a ton of time to troubleshoot right now so I figured I would ask here since there a ton of guys who know more than me about these things. I seriously thought it would wear in eventually but no dice yet so I think it might be a slight mechanical tolerance issue.
 
Huskydriver said:
I have emailed them if I don't hear back Mon I will try to call. I am sure he is busy getting Nucleus actions out as quickly as possible and doesn't have a ton of time to troubleshoot right now so I figured I would ask here since there a ton of guys who know more than me about these things. I seriously thought it would wear in eventually but no dice yet so I think it might be a slight mechanical tolerance issue.
Click to expand...

Phone works better...he is a standup guy
 
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I have talked with Ted on the phone a few times for 5-10 mins just asking questions about his products, he’s a great guy and will spend quite a bit of time going over things with you. He responded to my email, but it took some time.
 
Headspace problem or the counterbore is cut wrong. Any wear on the face or front of the bolt?
 
nexusfire said:
Headspace problem or the counterbore is cut wrong. Any wear on the face or front of the bolt?
Click to expand...

Zero wear on the face of the bolt where it would contact the breech of the barrel. Headspace is set .001+ go guage.
 
Forgot they are coned.

Extractor looks clean, but I'd pull it and run it just to see.

Yank the firing pin assembly too.
 
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Since the "click" is occurring with or without firing, I would pull the firing pin assembly and see if it still occurs. If the click goes away then I would look at the cocking ramp for some defect. If it still occurs with the firing pin assembly removed, I would look at the lugs and breech cone.
 
Update for those that were interested in helping. Spoke with Ted on the phone yesterday. He is a nice guy but he seemed a bit baffled by the issue. Told me I could send it up there to have them look at it but he thinks it sounds normal. Gave me the suggestion of swapping triggers to see if the cocking piece to sear engagement made any difference. I am running a triggertech diamond and swapped to a Timney Calvin elite with no change in feel that I could tell. He also suggested that if I have access to another Mausingfield ( which I do an, acquaintance has one), check if there is any difference after swapping bolts and reheadspcaing barrels. I wont be getting to this for a bit because my contact for another action is out of town till August some time. Will update further once I get a chance to swap parts and eliminate variables. Thanks.
 
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