Matt.Cross Posted September 17, 2011 Report Share Posted September 17, 2011 Ok, so here goes my range day thread to summarize my range day, and the first shots through my new MA TEN build.I got up early this morning, and called up my dad, and we caught an estate auction and stopped by the local gun show. I found 5 Magpul 20-round 7.62x51 mags for $100, and 20 rounds of .308 tracer for $17, an unbeatable deal in my book. Then it was off to Dick's Sporting Goods store for 5 boxes of Federal GMM and a laser bore-sighter. I took Frank and Goldilocks this time around, I had about four boxes of Bitterroot Valley Ammunition Company rounds that I bought some time back, 2 boxes were 168gr HPBT, and 2 boxes 168gr A-Max. These were to shoot through Frank just to get warmed up and to recheck the zero. I tested four of my new mags on those four boxes and managed to shoot with no malfunctions. Then it was time to switch over to Goldilocks and see what she was going to do. I loaded up my 5th mag with some FGMM, inserted the mag and pulled the charging handle and all was well. I fired my first shot, and when I went to pull the trigger for the 2nd shot, nothing happened. Absolutely nothing, no hammer fall or anything. I'd heard the ejected shell hit the ground, so I knew it had cycled, so I ejected the mag and ran the charging handle, and sure enough, it threw the loaded round out. Now, I'd been shooting well oiled this whole time, so I knew the action friction was at a minimum. I swapped the plastic PMag for a DPMS metal mag that I knew to be good, same problem, and now the bolt would either prevent the hammer from falling, or impede it from striking the firing pin. Taking the mag out and cycling the action by hand many times didn't improve anything, so I swapped the bolt carrier out of Frank into Goldilocks, and voila!, no problems with either the metal mags or the PMags. I put the Young Mfg bolt in Frank and ran a few rounds through it with both types of mags, no malfunctions. I concluded that the YM bolt carrier is simply incompatible with my Mega Ma Ten Monolithic upper, and so it will end up staying in Frank while I order a chromed bolt carrier from Fulton Armory, unless my SI Defense bolt carrier gets in first. Otherwise, the Ma Ten is a dream to shoot, I didn't even run a full box through it, but every round downrange impressed me with the shooting dynamic of the rifle. I can't wait to get it running right and spend another day on the range with it! It also taught me that I MUST get a heavier stock for Frank, I'm thinking he'll end up with a PRS. I'm also really impressed with the Bennie Cooley brakes, they work like a charm! The guys shooting beside me commented on how drastically the felt concussion was with the brake, albeit with a huge grin.Even with the problems, it was a good day at the range. I can't wait to get everything fixed and head back! Quote Link to comment Share on other sites More sharing options...
Jgun Posted September 17, 2011 Report Share Posted September 17, 2011 I'm intrigued here. First let me ask if I have your components correct. You have a Fulton chromed DPMS style receiver that works in both you Mega Monolithic upper and the other upper(don't know what that one is) and one of the new Young Mfg chromed stainless .308 BCG's that only work in the other, not in the Mega, is that correct? Have you taken any measurements of the two BCG's to see if there are any dimensional differences? I was planning to go with a Young .308 bolt carrier for my next build, because I like their AR 15 carriers so much. Do you think there might be something out of tolerance on the Young BCG? You don't have any bolt/barrel extension issues with the Young, do you? Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted September 17, 2011 Author Report Share Posted September 17, 2011 I'm intrigued here. First let me ask if I have your components correct. You have a Fulton chromed DPMS style receiver that works in both you Mega Monolithic upper and the other upper(don't know what that one is) and one of the new Young Mfg chromed stainless .308 BCG's that only work in the other, not in the Mega, is that correct? Mostly correct, the bolt carrier that works in both is not chromed, nor is it a Fulton, it's a DPMS bolt carrier. Have you taken any measurements of the two BCG's to see if there are any dimensional differences? No I haven't, I need to get a set of good calipers. I was planning to go with a Young .308 bolt carrier for my next build, because I like their AR 15 carriers so much. Do you think there might be something out of tolerance on the Young BCG? I don't think it's so much a tolerance problem with the YM carrier, it could be tolerance stacking. The YM carrier worked flawlessly in the DPMS. You don't have any bolt/barrel extension issues with the Young, do you?I don't think so, both bolts ran terrific once they had been swapped, and the bolt in the Young carrier was a Titan bolt matched for the Titan barrel they'd sent.Being that the YM carrier is so well made, and works perfectly in the DPMS upper, it's not going anywhere, I love that bolt carrier. I just don't think it will work with the MA TEN. With the prevalence of proprietary parts and no industry standard, it's practical to assume that tolerance stacking can and will catch up with you. That's what makes these experimental builds so exciting, it's all about finding what works, and what works really well. Quote Link to comment Share on other sites More sharing options...
imschur Posted September 17, 2011 Report Share Posted September 17, 2011 What trigger, more importantly what hammer? Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted September 17, 2011 Author Report Share Posted September 17, 2011 The trigger is the PACT SR Gold, I figured that it might be the problem too, but once again, after swapping the failure rate went to 0%. I found out that if you drop the mag and let the bolt seat, the carrier will rest VISIBLY farther forward in the upper than when you cycle it with a mag or loaded mag in. You can then put an empty mag in and the bolt will have enough drag that the carrier comes to rest where it should, and the hammer falls just fine, but when you're firing the cycling is a slightly different inertia dynamic. I'm unable to measure, but if I had to guess, I'd be willing to bet that from the face of the bolt carrier to the rearward shoulder (where it tapers down) measures less length than a Fulton or DPMS carrier would. If anyone would like me to send them my YM bolt to test this theory, I don't mind doing that. Quote Link to comment Share on other sites More sharing options...
imschur Posted September 17, 2011 Report Share Posted September 17, 2011 I was wondering if the carrier and hammer might be interfering with each other. So do I understand correctly, the carrier is not coming forward far enough to lock? Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted September 17, 2011 Author Report Share Posted September 17, 2011 I'm actually worried that the carrier is coming too far forward, and the hammer is being caught or impeded by the back of the hammer groove in the carrier. This is why I believe the carrier may have a shorter length from the face to shoulder. It is also possible I suppose, that the hammer groove is too short, or that my hammer is too long. Based on what my wife tells me, it's probably the latter... <laughs> <lmao>Oh, and to actually answer your question, yes the bolt locks. Quote Link to comment Share on other sites More sharing options...
Jgun Posted September 18, 2011 Report Share Posted September 18, 2011 Matt, if as Drew says, there is an issue with the Pact hammer being "taller" or the Young BC sitting lower, maybe you could take the upper off the lower, flip it over and measure the distance from the bottom of the upper to the bottom of the BC, and then swap in the Other BC and see if there's a measurable difference. If so, you would then have to determine if the difference is in the BC or the upper. If you find no difference there, maybe the difference is between the two different hammers/triggers? Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted September 18, 2011 Author Report Share Posted September 18, 2011 Matt, if as Drew says, there is an issue with the Pact hammer being "taller" or the Young BC sitting lower, maybe you could take the upper off the lower, flip it over and measure the distance from the bottom of the upper to the bottom of the BC, and then swap in the Other BC and see if there's a measurable difference. If so, you would then have to determine if the difference is in the BC or the upper. If you find no difference there, maybe the difference is between the two different hammers/triggers?I'm assuming the SR Gold hammer is longer in any case, but the DPMS bolt still clearly has the correct hammer clearance slot, from a compatibility standpoint anyways. What I'd like to determine is with regard to carrier dimensions, and clearance slot locations & dimensions. If the clearance slot (on the YM carrier) is the right size, it has to be in the wrong location (compatibility wise), I'm only suggesting that the reason it's in the wrong location is because the carrier dimensions could be different. If it had occurred to me, I would've swapped the bolts in the carriers and tested them, just to add that degree of comparison. It just didn't occur to me to try that because the YM carrier and Titan bolt functioned flawlessly in the DPMS upper.This is as good a reason as any to get myself a good set of calipers, I'm gonna have to Sherlock this one out for myself. <munch> Quote Link to comment Share on other sites More sharing options...
Jgun Posted September 18, 2011 Report Share Posted September 18, 2011 If you don't already have one you should have it for reloading anyway. I'm partial to the Starrett stuff, made in Massachusetts I think. Quote Link to comment Share on other sites More sharing options...
imschur Posted September 18, 2011 Report Share Posted September 18, 2011 My AADD keeps me from following a lot of descriptive text. With the bolts forward and locked can you measure from the end of the BCG to the edge of the upper with both uppers and both BCG's? That will give us a bit of a relative BCG overall length comparison. Did that question make sense? Quote Link to comment Share on other sites More sharing options...
imschur Posted September 18, 2011 Report Share Posted September 18, 2011 Yes get Starrett, Mitutoyo or Fowler and at least 4 decimal places. A good micrometer would be helpful too. Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted September 18, 2011 Author Report Share Posted September 18, 2011 My AADD keeps me from following a lot of descriptive text. With the bolts forward and locked can you measure from the end of the BCG to the edge of the upper with both uppers and both BCG's? That will give us a bit of a relative BCG overall length comparison. Did that question make sense?Well, I'm not very bright, but after thinking your question through to the point of near self-injury, it's quite clear now. Yes, I can measure it once I get the tools, no problem. Yes get Starrett, Mitutoyo or Fowler and at least 4 decimal places. A good micrometer would be helpful too.I used to have all that stuff, I sold it when I left the machine shop. Hindsight can be a major pain in the butt sometimes. Quote Link to comment Share on other sites More sharing options...
imschur Posted September 18, 2011 Report Share Posted September 18, 2011 Matt even a visual would be ok. From your description it sounds like you would expect one combination to have the BCG further in. Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted September 18, 2011 Author Report Share Posted September 18, 2011 Matt even a visual would be ok. From your description it sounds like you would expect one combination to have the BCG further in.Gimme a sec to grab the rifles and my camera. I'll use some empty casings and seat the bolts. Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted September 18, 2011 Author Report Share Posted September 18, 2011 DPMS w/ YM bolt carrierDPMS w/ DPMS carrier[img width=810 height=607]http://i214.photobucket.com/albums/cc158/jm_cross/DSC00043.jpgMa Ten w/ YM carrier[img width=810 height=607]http://i214.photobucket.com/albums/cc158/jm_cross/DSC00044.jpgMa Ten w/ DPMS carrier[img width=810 height=607]http://i214.photobucket.com/albums/cc158/jm_cross/DSC00045.jpgI can't see any discernable difference. I'm beginning to think I've overlooked a VERY important factor all along, and it makes me feel incredibly stupid, and rightly so. This new action is very tight, no big suprise there. What I haven't factored in so far (big duh here) is my HYDRAULIC BUFFER. When the bolt goes to seat, I'm betting the give in my hydraulic buffer isn't forcing the carrier all the way into battery. I'm going to put the standard buffer in it and cycle it by hand a few times and see if it locks & loads like it should. The rest of you can take turns kicking me and reminding me that when I think things through, it helps to think them ALL THE WAY THROUGH. <dontknow> <laughs> Quote Link to comment Share on other sites More sharing options...
imschur Posted September 18, 2011 Report Share Posted September 18, 2011 Well I meant the view from the end of the upper but I think you are right about the endine Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted September 18, 2011 Report Share Posted September 18, 2011 Isn't the YM a lighter carrier? I believe Endine's are for heavier BCG systems. If you are dead-set on using the YM, you might need to look into a CWS??? Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted September 18, 2011 Author Report Share Posted September 18, 2011 Well, testing has eliminated the Enidine, it's back to the drawing board. If I put an empty casing in the chamber and cycle the action (with the YM carrier), when I pull the trigger, the hammer will not move. However, if I unlock and pull back ever so slightly on the charging handle and THEN pull the trigger, the hammer falls every time. My solution is to either shorten my hammer, or send my carrier back to Young to have the hammer relief cut back a little further. My action is very crisp but my bolt is locking & seating every time, the carrier is just riding over the top of the hammer when it goes into battery. I can see a little mark at the very top of my hammer where the shoulder in the hammer relief is coming to a rest atop it.I will give Young a shout and see if they've had this issue and see if they'll fix it for me. Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted September 18, 2011 Author Report Share Posted September 18, 2011 Isn't the YM a lighter carrier? I believe Endine's are for heavier BCG systems. If you are dead-set on using the YM, you might need to look into a CWS???Actually, this one is hefting right at if not just slightly heavier than the DPMS carrier. If it's lighter, I sure can't tell it. Cycling it by hand with the standard buffer gave the same results as the Enidine. I will shoot it with the standard buffer until I feel sure that the action is wearing in to a slightly less crisp fit, but I don't think the Enidine is really the cause of my problem.I pushed in the piston of the Enidine with my thumb, and that SOB is one tough dude to compress, but it's not in the diagnostics picture now regardless.I have an e-mail going through to Young Mfg now, we'll see what they have to say about it. Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted September 20, 2011 Author Report Share Posted September 20, 2011 Young said to ship my bolt carrier back and they'd happily fix it and ship it back to me. I'm hoping that since they're not marketing it yet as a finished product, they'll take aftermarket triggers into consideration on their final design. As it stands, I'm simply waiting to hear back from them on whether or not I should send the trigger with it, so they can take measurements and perhaps amend their design to accommodate aftermarket triggers. Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted September 24, 2011 Author Report Share Posted September 24, 2011 Ok, so I haven't gotten my bolt carrier sent off just yet, but it will ship after today's range session. In the meantime, I thought I'd show you guys another picture of the key difference between the bolt carriers.I'm sure Young will have it fixed in short order, and now I have a pic to send them. Quote Link to comment Share on other sites More sharing options...
imschur Posted September 24, 2011 Report Share Posted September 24, 2011 Thanks for posting that. Sure is sexy though. Quote Link to comment Share on other sites More sharing options...
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