Montana3gunner 13 Posted March 31, 2014 Report Share Posted March 31, 2014 I have a suggestion on an improvement to the MKA bolt I'd like to throw out to forum members for discussion.... I tried to dig up a pic of an MKA bolt in the interweb but was unsuccessful and I'm to busy/lazy to take my MKA apart...so maybe someone has one laying around and can post a pic of one (preferably the bolt face and some side profile). I'm wondering about a possible improement to the little piece of metal (not sure what it is called) that is just below the bolt face that picks up the next round from the magazine. As the bolt blows back under recoil, this piece of metal rides over the top of the next round. The problem as I see it, is that causes tension on the bolt...potentially slowing it down. This tension is increased with the more rounds there are in a magazine (due to increased spring pressure). To overcome this tension on the bolt, the gas system has run with have enough gas to dependably cycle on the 1st round in the magazine, and would need less gas to cycle the last round (I'm not sure what the difference between the two would be, but push on a 15 round mag sometime with 1 round and 15 rounds and note the tension difference). This means that we have to run the gas system with significantly? more gas than we'd like to, at least for half the magazine. This increases recoil, increases wear and tear, and may have an effect on dependability? Would it make sense to have a bolt where the little piece of metal retracted into the bolt on it's way back, but locked into place as the bolt moved forward so it could pick up the next round in the magazine? This might facilitate the abiltiy to tune the gas system to use less gas and possibily using a lightened bolt and carrier (similar to a JP Low Mass Carrier or others), which might improve recoil? Hope I explained this clearly...probably not! I may need to post a video so I can explain what in the heck I'm talking about. Quote Link to post Share on other sites
james lambert 3,059 Posted March 31, 2014 Report Share Posted March 31, 2014 Not an option The bolt has other issues and is being addressed Jim Quote Link to post Share on other sites
Brett248Vista 5 Posted March 31, 2014 Report Share Posted March 31, 2014 Jim, What bolt does the TAC21 come with? is it an off the shelf MKA part or do you do custom bolts for the TAC's ? Quote Link to post Share on other sites
james lambert 3,059 Posted March 31, 2014 Report Share Posted March 31, 2014 We are making bolts from chrome moly bar stock. The originals are cast. They are not available to the public yet. Jim Quote Link to post Share on other sites
Montana3gunner 13 Posted March 31, 2014 Author Report Share Posted March 31, 2014 Jim, thanks for responding. I know you are super busy. Does that little protrusion have a name? It appears that thing has two purposes 1) As the bolt is moving rearwards, tip the next round in the mag up so that it comes out of the mag tilted up towards the chamber 2) As the bolt moves forward, push the next round out of the mag. Is this correct? I am really excited for the A1. Kudos to you guys for taking it on. Quote Link to post Share on other sites
james lambert 3,059 Posted April 1, 2014 Report Share Posted April 1, 2014 Its only function is to strip rounds from the mag. It has no effect on bolt open cycle Jim Quote Link to post Share on other sites
Goodwin 1 Posted June 8, 2014 Report Share Posted June 8, 2014 (edited) any word on when your replacement bolt will be ready Jim Edited June 8, 2014 by Goodwin Quote Link to post Share on other sites
james lambert 3,059 Posted June 8, 2014 Report Share Posted June 8, 2014 We are working full blast putting TAC12-A!s out the new bolts are awaiting a new machine 2 Quote Link to post Share on other sites
SHOTGUN MESIAH 855 Posted June 9, 2014 Report Share Posted June 9, 2014 Get er' done . Quote Link to post Share on other sites
Goodwin 1 Posted June 9, 2014 Report Share Posted June 9, 2014 they will work in the xn model correct? Quote Link to post Share on other sites
james lambert 3,059 Posted June 9, 2014 Report Share Posted June 9, 2014 Yes its An XN Quote Link to post Share on other sites
Goodwin 1 Posted June 10, 2014 Report Share Posted June 10, 2014 thank you Jim Quote Link to post Share on other sites
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