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Discussion Starter #1
So I have finished my m1919 and was pretty happy with everything. Even my rivetting.

But.

It seems my internals are dragging. I am really familiar with M2 and I don't think they should be binding like this. One thing I am sure of is it isn't the rivets. They were countersunk and buffed to the plate.

I can't figure it out. The parts will go into battery it just is not smooth at all. I even tried a bit of lapping compound.


Any advise for me? I see no serious wear marks.

KMP Plate
Izzy kit
Parts milled by one of our own here.

I could use some advice.
 

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Video or pictures might help. Is your receiver box square? Have you checked the head space? Also where do you live? There are people all over the country on here and most are willing to help
 

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Dragging where?

I would suggest close inspection and pictures may help. Do you have Dykme or something similar to use? Is the receiver box square? Try removing the barrel and see if the parts still bind, if not then a guess is that something is out of alignment. The areas that are milled on the internals are clearance cuts, you shouldn't see drag in these areas. Are all of the parts well lubed? No remaining blast media causing issues?
Anyone nearby that has another set of internals you could try?
FM types faster than old people, also posts quicker "I'll take it" than old people.
 

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Check the above mentioned items.

80% plate or 100 ??...check charge handle slot.

Is your bbl shroud strait?.....remove bbl as mentioned above. Get a long straight edge and check shroud alignment in relation to receiver box.
 

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Discussion Starter #5
I'll take video tomorrow.


I am pretty sure it's square and the headspace is good.

If I barely touch the barrel extension they will hammer home quick.

Sometimes it takes some effort to get the bolt back.

More to follow. I am in destin, fl
 

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Discussion Starter #6
Check the above mentioned items.

80% plate or 100 ??...check charge handle slot.

Is your bbl shroud strait?.....remove bbl as mentioned above. Get a long straight edge and check shroud alignment in relation to receiver box.


Will do this as well.

It was a 100% plate.
 

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Well it could be a number of things and among the box be out of square or the jacket the booster bearing could be fowled up. your plates could be warped also so check the trunnion surface to ensure there are no nick or burrs and the barrel slides freely. I would just start with process of elimination and you will find it. Here are a few others you can check but you have certainly come to the right place to find answers.
is the breech lock cam screw too tight?
check the charging handle slot location
correct depth of machined parts
is the barrel itself bent? not common but it does happen
ensure the parts are not burred or dinged
 

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If it clangs into battery and its a bear to open afterwards (like needs rubber mallet on the bolt handle) it sounds like your headspace is wrong. You should double check the process you are using to be sure it is correct before trying anything else. If you need talking through it PM me and Ill give you my number.
 

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Heh, quick check: remove the barrel and check the internals for fit/function.
 

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I had a rivit or two that were ever so slightly sticking out above the surface of the side plate that made the internals bind up. Had to get in there with a small file and take just a hair off of them to make it all work smoothly. I've also had a new build that took a while until everything worked well. Took 150-250 shots for all the metal bits to like their neighbors and function well together.
 

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Had same problem with a few inside faces of rivets on my first build. Ran file down inside then touched it up/polished it with some sandpaper
 

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Having built a few of these, I've found that there are some combinations of parts that do not like each other. From what you describe, another possibility is the breech lock and breech lock cam. Sometimes, swapping these parts in can make all the difference. If you have an extra breech lock, or even cam, try swapping those out and see if anything changes. One part at a time. If you've tried everything else suggested here, that's one more thing.
 

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I like Toolman s suggestion about checking if the breech lock cam screw is too tight. I didn't see that one repeated anywhere and thought it may have been missed in the text
 

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Also check to see if the breech lock is not in backwards, bevels need to face the breech lock cam.
 

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m2

Make ABSOLUTELY sure the receiver box is not warped , easy to do if over pressure on some of the rivets, I'm having the same problem with one I bought off here, it is bent .030, having to take it apart and redoing it.
 

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I had a barrel jacket screw(that prevents the jacket from unscrewing)that was a little to long and it would slightly cant the barrel to one side which would the push against the inside of the booster(it would not enter the booster concentrically) which made it hard to close and open that last small amount by it's lockup phase.
 

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I also agree with trying the internals without the barrel. This will help determine if there are issues from the trunnion forward or with the internals.

I do recall that someone else was having similar issues and it turned out that the bolt was riding the top edge of the RSP denial island, causing the bolt to cant at an angle, resulting in binding. The bolt just needed a bit more material removed for the semi machining and the binding issue was gone.
 

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same problem

I had the same problem check the barrel ext see pic the red line need ground down
semi barrel ext.jpg
 
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