huggytree Posted November 10, 2017 Report Share Posted November 10, 2017 just curious on this one...i know it wouldnt go in/out.....id guess it could scuff the finish on the side of the receiver if pushed in a bit....id assume there could be a mod to make it not be able to go in/out what wears out on a MP40 bolt that you would need to swap to a FPB just trying to get educated Link to comment Share on other sites More sharing options...
Sandman1957 Posted November 10, 2017 Report Share Posted November 10, 2017 I can't understand what you are asking. Do you mean are they interchangeable? Yes, but you have to use the spring set from the FPB as well. I shoot mine with a FBP bolt and spring set. Link to comment Share on other sites More sharing options...
huggytree Posted November 10, 2017 Author Report Share Posted November 10, 2017 (edited) Im talking specifically about the original bolt charging handle before they modified the bolt and the receiver for the extra safety Would a fpb bolt work on one of these unmodified guns work. The original mp40 didnt have the safety pull push safety on the charging handle. The fob bolt has this feature. Can this bolt fit on a tube not modified for the push pull bolt Edited November 10, 2017 by huggytree Link to comment Share on other sites More sharing options...
Black River Militaria CII Posted November 10, 2017 Report Share Posted November 10, 2017 Some MP40s don’t function very well with the FBP parts and I’ve had a couple in the shop that needed some light work to function properly, but most are drop in along with the spring housing. The FBP bolt has the firing pin milled into the face of the cartridge base recess, so unlike the MP40, there is no separate firing pin and the spring housing has no firing pin on it.The most fragile part of the MP40 bolt is the sliding safety cocking handle since it is held in place with a rivet and the rivets eventually lose their grip due to the fierce repeated high rpm impact from the bolt going into battery. I have lost count of the number of MP40 cocking handles I have repaired after they have come loose. Often they fall out. Or the web between the indexing holes in the bottom side of the sliding handle fracture. Original sliding handles are becoming scarce and repros come and go as maker’s sell out and on’t make any more. The repros are easy to tell from the originals. Most original handle are marked with a maker’s mark, “ayf”, etc, but there are others that are not marked.There are several types of cocking handle studs that rivet to the bolt with different types of shallow divots for red and white paint that indicate safe or unsafe.Extractors also break, but generally are quite durable. Firing pins break as well.Use of the FBP parts is mostly done to protect the original matching bolt, firing pin and spring housing from damage. The bolt itself is not really possible to damage. FWIW Link to comment Share on other sites More sharing options...
Petroleum 1 Posted November 10, 2017 Report Share Posted November 10, 2017 Bob...the gun huggy is looking at has the old style hook charging handle and the receiver does not have the notch cut for the newer style charge handle. I know you have said in the past the hook style has not been a problem with snapping off or coming loose, is that true?? also would the FBP assembly work on a receiver that does not have the safety notch milled into it??thx Vinny Link to comment Share on other sites More sharing options...
Black River Militaria CII Posted November 10, 2017 Report Share Posted November 10, 2017 Over quite a few years, have only had one MP40 bolt with the early style cocking handle in for repair so one could assume that they are less prone to loosening up. There are far less of them on guns, as well, so that needs to be taken into consideration.there should be no problem with use of the FBP bolt in an MP40 due to the cocking handle style. Link to comment Share on other sites More sharing options...
Petroleum 1 Posted November 10, 2017 Report Share Posted November 10, 2017 Also i read somewhere that the FBP bolt assemblies do not work well in the tube guns possibly due to the lack of grooves in the new tube ?? Link to comment Share on other sites More sharing options...
Petroleum 1 Posted November 10, 2017 Report Share Posted November 10, 2017 Also i read somewhere that the FBP bolt assemblies do not work well in the tube guns possibly due to the lack of grooves in the new tube ?? Link to comment Share on other sites More sharing options...
Black River Militaria CII Posted November 10, 2017 Report Share Posted November 10, 2017 What grooves? There are no grooves on the interior of an MP40 receiver. Look, just about anything can be modified, repaired, altered, etc, etc to fit properly especially with very minor issues. Every MG can be a bit different in very minor details from its generic type and minor variances can create problems especially with cross-use of another similar type of MG. FBP parts assembled in an MP40 reman tube is a perfect example. Modifying the AR/M16 platform with all sorts of different barrels, bolts, and other parts has created a whole industry specifically devoted to fixing the reliability and function problems of these mods that were never envisioned by the designer or the manufacturers. It’s just part of the entertainment of owning MGs......FWIW Link to comment Share on other sites More sharing options...
huggytree Posted November 10, 2017 Author Report Share Posted November 10, 2017 these grooves Link to comment Share on other sites More sharing options...
Petroleum 1 Posted November 10, 2017 Report Share Posted November 10, 2017 (edited) see my post below :-) Edited November 10, 2017 by Petroleum 1 Link to comment Share on other sites More sharing options...
Petroleum 1 Posted November 10, 2017 Report Share Posted November 10, 2017 I know you are testing me Bob but i used the wrong word. I meant to say ribs. They were there to space the bolt off the receiver so that dirt and grit wont jam it up Link to comment Share on other sites More sharing options...
huggytree Posted November 11, 2017 Author Report Share Posted November 11, 2017 Ribs for Dirt/Debris...making the bolt run in adverse conditions 1 advantage over a wilson/erb tube in case you plan on rolling in the dirt using a MP40 in WW3 Link to comment Share on other sites More sharing options...
Grasshopper Posted November 12, 2017 Report Share Posted November 12, 2017 Hi All, A short answer: You can use the FBP bolt assembly in an early MP-40. Just don't push in the bolt lock safety. I ran an FBP bolt in a MP-40 tube gun for years. The tube had not been cut for the later style bolt safety. Since I didn't have a hook type handle, I milled the receiver for the later style cocking knob/safety. Looking back, I wish I'd just found a hook cocking handle. This particular tube gun likes ammo loaded at least as high as quality factory ammo. Target loads/lighter handloads are not reliable. I could clip the spring in the FBP bolt assembly but what is the fun in that. Grasshopper Link to comment Share on other sites More sharing options...
Petroleum 1 Posted November 12, 2017 Report Share Posted November 12, 2017 Hi All, A short answer: You can use the FBP bolt assembly in an early MP-40. Just don't push in the bolt lock safety. I ran an FBP bolt in a MP-40 tube gun for years. The tube had not been cut for the later style bolt safety. Since I didn't have a hook type handle, I milled the receiver for the later style cocking knob/safety. Looking back, I wish I'd just found a hook cocking handle. This particular tube gun likes ammo loaded at least as high as quality factory ammo. Target loads/lighter handloads are not reliable. I could clip the spring in the FBP bolt assembly but what is the fun in that. GrasshopperGood info ty...is the spring on the FBP assembly stiffer than the factory German one?? Link to comment Share on other sites More sharing options...
huggytree Posted November 12, 2017 Author Report Share Posted November 12, 2017 i did a bunch of reading on the FBP and everything i saw said to use the MP40 factory spring, that the FBP was too strong.... Link to comment Share on other sites More sharing options...
smkummer Posted November 13, 2017 Report Share Posted November 13, 2017 I have shortened the recoil spring on a FBP spring assembly and when the gun gets a bit dirty, it sometimes runs away. The sear cut on the bolt is different than a MP40 bolt. My FXO MP40 is original. Link to comment Share on other sites More sharing options...
azboater Posted November 15, 2017 Report Share Posted November 15, 2017 If any one wants to buy my FBP assembly let me know,I couldn't get it to work in my matching numbers C&R MP-40 (But I am not Mechanical, maybe someone else can get it to work I did not play with or shorten the spring) so I bought a non matching MP-40 bolt & firing pin assembly and both work greatmore money, but made for the gun Link to comment Share on other sites More sharing options...
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