svtboy76

Montana3gunner, I'm wondering if you were having light strike issues or if you replaced your trigger group to reduce your trigger pull? Based on the issue of light strikes, shipping only the lower off to have the trigger group replaced would not guarantee a fix. It would appear there was an interaction between firing pin friction and hammer velocity. The good news is that its now fixed! So, the Wolff XP spring worked, I went out and shot a full 50 round sporting clays course with no FTF or FTE. This was loading through the magazine as well as single rounds through the ejection port. As always, there were plenty of shocked looks at the Eotech, always good for a laugh. Image of the new primer strikes, good penetration but it is not piercing the primer. Thanks for all the comments and assistance. To summarize how I think a person could fix a light strike issue: 1. Disassemble MKA 1919 shotgun and remove assembly lube. Lightly relube. 2. Remove bolt and remove firing pin from bolt. Polish firing pin contact surfaces and inside bolt contact surface. 3. Remove hammer and remove factory hammer spring from hammer. 4. Reduce hammer trunion diameter using a lathe (or other method) to .27" and install Wolff XP AR15 hammer spring. 5. Reassemble shotgun. I'm thinking next I'll work on how to mount a better handguard!

A status update on what I'm doing to get this running right. The stock trunion diameter is .353", and the inside dimension of an AR15 spring is .32". A DPMS hammer is .27" as there needs to be a gap between the spring and trunion for it to function correctly. I machined down the trunions on my lathe to .27" and then reassembled using a DPMS hammer spring I had handy. Everything went together no problem and the shotgun functions as expected with no additional force required to chamber a shell, etc. However, taking it to the range shows that a standard AR15 spring is not sufficient to fix the issue as I was still experiencing about a 50% failure to fire issue. The good news is I have a Wolff XP AR15 spring on order that I will be installing this week. Looking at the depth of the strikes from the last trip, I am confident this higher rate spring will finish off this project. I'll report back in a week. Pictures of the freshly machined hammer with a AR15 spring.

Ok, so the screw broke on one of the holes. The screw goes through the buttpad and into the plastic lower to hold it on. If you applied a bit of force to the buttpad with the first screw out it should come off and then you could use a set of vice grips to unscrew the remainder of the screw from the lower. There's nothing special about the screws, you should be able to get a stainless replacement at your hardware store (and its hidden once assembled so it does not need to perfectly match). Sorry to hear about the problems, you definitely need to take it apart after purchase and clean the assembly lube, then reapply a light coating of your normal lubricant before using it (I would also take apart the bolt and clean that as well, around the firing pin especially). Some seem to have issues, most don't from what I hear. The good news is that it is easy to work on, the parts are well made and I think its well made for the price! Hopefully you can get it running right!

Attached are the pictures off the offcenter strikes. Notice these shells were run through more than once and still didn't fire (although plenty of others in this batch did). . These are Winchester AA Supersport Sporting Clay Target Load Shotshells

Falcon34, sure I can post some photos this evening, not sure if a spare part/s would fix the issue though. As an engineer I understand manufacturing variability but based on this conversation some of the things that would improve this issue are design related such as: Hammer spring stiffness (increasing the spring rate would improve the hammer impact force, there are few negatives here as this is what Jim is providing. Trigger pull force is reasonable even with increased spring stiffness. The best situation would be if multiple spring stiffness were available to tune out this issue.) Firing pin length (a longer pin would increase force transmission to the primer, mine sits about 1/16" within the bolt at rest. Of course increased length would increase the chance of a slam fire) Tolerancing between the barrel/bolt (on my shotgun, when the bolt is fully forward in the firing position with a shell loaded, the bolt still has limited freedom to rotate at the point where the hammer contacts the firing pin. This means not all of the force is moving the firing pin forward on impact with the hammer.) Retention of the firing pin within the bolt. the only thing preventing lateral and vertical movement of the firing pin is the firing pin spring. If the hammer applies a load off axis to the firing pin, there is opportunity for the pin to rotate within the bolt and contact the bolt. I attempted to improve this by polishing the pin and inside bolt surfaces (this helps). If you have ideas for what we can try to fix this issue I'm very interested to discuss, thanks for offering to help!

Sorry for the delayed response, vacation and all! I got into my AR parts bin last night to see what there was to work with. The answer is not much! There's no compatiblity between AR hammers (too short, impact point is too low on the bolt with an AR hammer in place), springs (as Jim mentioned they don't fit over the MKA hammer) hammer/trigger pins (AR pins are too short) or even the firing pin (AR is shorter)! Even though it has a lot of similarity to an AR, it definitely has a different dimensional layout. the MKA hammer could probably be drilled out and a smaller trunnion installed, but its probably not worth the effort. Also of interest is that a person should be concerned about how many times they take the trigger group out, the material in the lower looks like it would only be good for pressing the pins in and out five or so times before it might get loose. Jim, I'll send you an email. I'd like to get one of those hammers (and a handguard while I'm at it!). Thanks.

Jim, thanks for the response and for replying to my email on the topic. I did notice the hammer spring is weaker than the other springs I have at home (DPMS and Wolff) however they are not compatible due to the hammer differences. It sounds like Firebird has a custom hammer that would allow a wider variety of hammer springs, but at this point those are only being installed on the firearms in your facility, correct? I am also seeing the offcenter strikes you are mentioning, the bolt allows offcenter movement of the pin within its range and the spring does not restrict that movement. Lastly, when the pin is struck by the hammer you can see the bolt slightly shift implying that not all of the force is being transferred from the pin to the round, some is misdirected into the bolt. My goal right now is to locate a hammer/higher rate spring that I can install that will work with the existing trigger/disconnector. I do have a 3 axis CNC mill that I can use to tweak any imcompatible geometry. I'll share my results. If I'm unsucessful, I'll be sending it off to Firebird. Thanks for all the feedback!

Dave, thanks for the response, I did check that. I think I've taken it apart 20+ times now, its getting pretty easy to do. Overall I like the mechanics of the gun, what is interesting is that it is very similar to an AR15 but a lot of the parts don't appear to cross over. I'm going to start playing around with trigger group components, I'll share what I find out. Thanks.

So far the looks have been a combination of sympathy from my friends as it clicks with no bang and confusion from the rest! The gentleman manning the range desk told me I couldn't take a rifle out on the sporting clays course, I had to show him I had a choke installed to convince him it was a shotgun. Good times. Tim, I'll post over on the Firebird forum as well, hopefully Jim has an idea that doesn't involve me sending in my gun (leagues start in a month and I hear his queue is long).

Good morning, I'm wondering if the group can provide an opinion on what to do next for a failure to fire issue. I purchased my MKA 1919 a few months ago and have taken it out to shoot several times. Getting failure to fires on 50% of my shots, using multiple types of ammo (Nitro Gold #8, Top gun target #8, Rem Slug). The firing pin is just not striking the primer hard enough, leaving a small dent. I am following all gun safety protocol and after observing any new issue I am taking the gun apart to make changes, I've also reviewed the steps below with our gun clubs master gunsmith who unfortunately does not have any experience with the MKA 1919. Here's what I've done so far: 1. Stripped the shotgun down and removed all factory lubricant, applied a light coat of oil on all moving surfaces. Same issue. 2. Disassembled bolt, removing firing pin and firing pin spring. Polished pin to 2200 on contact surfaces, polished inside of bolt. Reapplied light coat of oil. Same issue. 3. Replaced trigger and disconnector with Tromix unit (I did not expect this to help much). Checked hammer spring, it was at 180 degrees. Bent it slightly to attempt to get more impact force to the pin. Same issue. 4. Purchased a Wolff extra power hammer spring from Brownells, it does not fit the MKA 1919 hammer. Does anyone know which AR15 hammer/trigger group might be compatible? 5. Not recommended for anyone to try! I trimmed back the firing pin spring by one coil. The advantage of this is that I noticed that the hammer was then able to completely compress the firing pin when fired, unfortunately this did not allow enough retention force for the firing pin and I witnessed a slam fire as the bolt closed. Does anyone know where I can get another MKA 1919 firing pin spring, or does anyone make a replacement (Wolff perhaps)? Thanks for the help, I'd prefer not to send this out as I enjoy working on my own guns. I was trying to build this up as a sporting clays gun with an Eotech I had in my safe but its not working out as expected so far!

Wow, good info. I'm guilty of all of those things . . . I have just been shooting slow fire at the two ranges I go to. I will purchase the practice deck, that's a great idea. I am still a "jumpy" shooter, reflex with the noise. Wearing earplugs and the electronic hearing protection helps but I can see how I would get more tense the longer I'm at the range. Hopefully more practice will improve that. Good point on how being tense while shooting is going to potentially alter my shooting behavior. Yes, they are all going low (maybe 5% bad shots go 3-5" low at 25 feet). I'll focus more on dry-firing until I can reduce that tendency . . . Both ranges I attend seem to have very strict rules "no rapid fire, double tap, one target size, etc". Because of that I feel like there's very little flexibility in what I can do with live ammo at my range and I only use my holster, practice magazine changes, etc at home. I'm assuming if I can join a club in the next few months I'll be shooting with a different type of shooter and perhaps I can practice some of those things . . . thanks for the help!

Afternoon, been reading the forums for a long time but haven't had a question worth posting till now. I've been shooting now for about 2 months, an Angus tuned Shadow. Great gun, very happy with it. I've been trying to shoot 100 rounds a week in a single session (seems the most economical way to go to the range and still build my skills). One thing I've noticed is somewhat like when I play darts or pool I'm more accurate at the beginning of the range session than the end (4 inch spread for 18 shots at 25 yards vs. 12 inches + later). This is slow fire, one shot every 10 seconds or so. I don't feel like I'm getting tired, I'm in good shape, I don't see additional movement of the sights later in the session, any ideas? My palms do sweat and I have a towel for that. I'm trying to grip the pistol in the same two handed grip each time I load a new magazine. Thanks for the help, I do love the site, tons of great info!