LuckyIrishman bolt release modification..

1/7/2024 update: 140 rounds fired.  Good reliability - still having stuck-bolt issues on bolt-lock.

Gun reliability remained good, and did some gas setting adjustments, now that the gun is a bit broken in.  Accuracy was still decent, but only that.

With 55 ball and 55 HPBT giving in the 1.6-2.2 MOA level performance; as was MK318, which is decent enough. (-3 and -2 gas levels; and -4 gas for the MK318)
60 gr Nosler was terrible, and couldn't even keep on the paper (Ah Nosler) -5 gas
69 Sierra Match King opened to 3.1 MOA (-6 gas)
73 gr Berger's and 77 gr MK 262 were more meh, at 2.5-3.5 MOA level (-8 and -6 gas respectively)

The 2.5X scope seemed to work well, and the gun was a pleasant joy to shoot.  And the new handguard looks and feels great.  Didn't shoot mag-dumps to really warm it up, but did try steppign it up some, on some targets - but never was able to get it warm enough to comment on that.

Accuracy and zero were good enough that a 20 round mag got 20 hits on a 200 yard gong (12"), so decent enough.  I'll probably reach out to KelTec customer service this week about the bolt sticking, basically the bolt carrier, the "lower receiver", the bolt-stop itself, and the receiver (upper), are the parts involved and have too much play.  I think with the bolt-release bent in just a bit, that probably will fix it.  Or the guides in the inside of the molded "lower" receiver will do it, I suspect as well.  I'll see what they say.

Total round count: 680 rounds fired through this rifle so far.

I emailed KelTec and asked if the had a thought on the sticky bolt release issue, and if the could send a new bolt stop.

They did.  But alas, I don't think this will help.  Dimensions are same as current one.  You can see in the below photo where I have the new one engaged against the end of the old one.



I guess my best next option is to increase the size of the internal alignment nubs (you can see one in the bottom left of photo), maybe with JB weld or electrical tape..

You sound like a Keltec owner 🤣

While I'm all for do what you want with your gun even if it doesn't necessarily make sense, but have you given any consideration for why you have that handguard?

Spending extra money for an aluminum rail that heats up much easier than plastic, the point of which is to give you more space to mount accessories. And all you end up having mounted is a vertical grip (which could have just as easily been mounted to the original plastic handguard) and plastic rail covers to cover up all that aluminum so you don't burn your hand on it (which wouldn't be needed on a plastic handguard). And unlike an AR15 you don't even get the benefit of free-floating your barrel.

Again "It looks cool" is as good a reason as any, but unless you plan on actually mounting a bunch of stuff to the front of your rifle. It just seems like spending extra money to end up having to worry about how you grab the thing lest you burn yourself. Why?

It's a fair question.  My own answer - the factory plastic stock is hideous.  I mean just hideous.  It also is sort of meh - it gets hot.  A lot hotter than I was expecting.  Almost uncomfortably hot.  While at the same time doing a terrible job of helping shed heat, since it's an insulator.  Where the aluminum should allow the whole system to cool much faster.  And with that, not overheat as much at a more moderate pace of fire.   Finally, with my own aluminum; it's stiff enough that I'm comfortable mounting one of the more recent ultra-small flashlight laser combo's on there, and it holding zero; where the plastic would not.  In addition, the aluminum is thinner, so fits the hand better.  In my own case, i have not mounted a grip or plastic heat protectors on it, as I want it to be a radiator.  But we'll see, after a couple summer runs at high round count, perhaps I'll change.  

One thing I've learned with aluminum handguards - keep gloves around.  ALways.   Actually more for the cold, than the hot.  Watched a friend learn that the hard-way during an all-night hog-hunt at 45 degrees.  You don't need gloves at 45 degrees for just your hands outside.  But if you are holding a bare aluminum handguard, you sure do.  It will suck the heat out of your hand at 45 degree's something fierce, to the point you can't even use it.

So, being a KelTek owner now, and having the spare part in hand already anyway (which will be a Major PITA to install, if I have to), I figured eh - let's see what we can do here.  It's a KelTek.



Plan:  Apply a light application of JB weld to the side of the end of the arm, so as to guide it away from the edge of the upper receiver rail just a tiny bit.  note while it's a loose fit in the lower, the bolt-lock lever arm rides inside the rail in contact with the rail, of the upper (see below photo), when assembled.  But only when it goes up, to lock the bolt.  Theory is, if I can get that arm just a bit off that rail and push it inwards just a tiny bit, then it won't wedge between the bolt carrier and the rail upon contact.  that's my theory at least!

So, I mixed up JB weld.  Degrease sprayed the piece, and taped around the area to avoid carry-over.  I then wedged the arms in a bit, for better temporary access.  

Mitigation action 1)  and with a toothpick, applied a tiny bit of JB weld on the sides at the end of the arm, and then scraped it clear with a little angle on it, to prevent interference with the receiver rail as it goes up, and to aid pushing the arm in, if it contacts there.  This might actually have worked, though no live fire yet.  I am trying to simulate by pulling charging handle back and then releasing it so it will impact with vigor, to simulate live fire application - but of course, those no live fire like live fire, so we'll see.  So far, this actually appears improved... maybe.  I will say, working with JB weld is... tricky.  So this took a few attempts, and isn't perfect what I wanted - but I did get some on there I think how I want... I think.

Mitigation action 2) I also put a little JB weld on the arm across from where the alignment strut is in the frame of the lower.  Thinking maybe that will help push the rails in too, if they try wiggling out.  TBH, I don't think this actually worked and I probably didn't put near enough here.  You can't really see any of what I'm talking about in the photo, but if you have an RDB, they have a plastic molded spot (under the two sling hook spots actually), that is supposed to contact the side of the bolt-lock arms to keep it aligned, and mine are way too short to actually do jack shit.  So if I can make them bigger, maybe that would help.  Or in this case, I put JB weld on the arm, to make it potentially bigger, to contact those two bump spots.  But not enough, so I pretty much failed to actually implement the idea right - though the idea itself still isn't a bad idea.

Mitigation action 3) NOT YET DONE.  So after some deeper investigation, what I'm seeing is that the bolt carrier has some wiggle in the receiver.  It's not visually obvious in the photo, but pushing it to either side with the hands, does create a gap.  Interestingly, the gap is only on the right side, ( Starboard Side, we'll say; per gun assembled and upright).  The Port Side doesn't have enough of a gap, for whatever reason.  And sure enough, there's already a scratch on the rail inside the receiver, on the starboard side, exactly there.  So, Mitigation action 3, is to just file down the starboard side of the bolt stop a touch, so that it engages on the Port side, and not the Starboard side.



Mitigation action 4) NOT DONE YET.  I picked up a stick-welder for like $60 off the Amazon Deals threat in TEAMS.  So I might just weld a very slightly fatter/bigger face where the piece contacts the Bolt Carrier, so it literally can't fit in the gap.  In theory I could try that with JB Weld, but I don't trust JB weld to take a job that involves being directly impacted like that. (can I?).  Problem there is I likely will have to pull the part out to do that job, which - see above, will be a MAJOR PITA to remove from the plastic lower frame.  And of course take care not to increase the total mass appreciably, so that the mag-spring tension will still lift it reliably quickly.

Lazy... this reads like a nightmare.

Especially the part about buying a 60 dollar stick welder with the intention of making things better...

you think this is bad, you should see my accuracy tests with my Desert Tech!  

"And my dust cover experience and "Customer Service" "Support!" interactions with Steyr!

All of this is just far to detailed a deep dive into a sticky bolt release, on the RDB.

And a fair answer. Personally I kinda like the way the blocky forend of the RDB looks. Though a 20" barrel does round out the proportions better than the seemingly more common 17". I do agree that a it would probably benefit from atleast a basic heatshield in the handguard like your typical AR handguards. Certainly enoough room in there to Bubba something up if one were so inclined.

It worked!  

My scheme to mitigate the dreaded RDB stuck-bolt-lock issue some folks have, totally worked.  I ran close to 20-30 magazines to bolt-lock today, and none of them had any problems after my simple JB weld trick.  Gun ran smooth and easy with the factory bolt-release button all day long.  Whereas before this, about 80% of my mag-locks were locking up the gun requiring a high-vigor manual cocking action.

Here is Lazy's guide to eliminating RDB stuck bolt issues.  
Short answer: A spot of JB Weld on the outside of the bolt-lock tines, to prevent them from being thin enough to fit and wedge in the gap between the bolt-carrier and upper receiver; but light enough application to not affect mass and free-motion of the bolt-stop mechanism.

Long answer:
Problem statement: For those experiencing the operations hang-up of the bolt-getting stuck in the lock back, to the point where the release lever isn't usable, and it takes a high vigor manual cocking action to break free.  
Cause:: This is caused by tolerance/play between the receiver rail and the bolt-carrier, allowing the tine at the end of the bolt-lock to get wedged between the reciever and the bolt carrier, locking the gun up; after the last round of a magazine.

Corrective action procedure:
Step 1: Identify which side this is happening on.  This will be evident by scratches forming on the inside of the receiver rail, where the bolt-stop tine (the end of the 4" long bolt stop part, where it engages the face of the carrier to stop the bolt).  In my case it was on the right (starboard) side.
Step 2: apply protective tape on the inside of the lower receiver so that drips and overages don't get stuck on the ejection chute outside wall or on the plastic lower.  (I used electrical tape applied to the inside surfaces flanking the bolt-stop tine; for both tines.  (where "tine" is the end of the long stamped-metal bolt-stop that engages the face of the carrier)  I.e. Tine is clear, but the receiver components around it are now covered in electrical tape for the duration of the application procedure.
Step 3: JBWeld and toothpicks.  Carefully apply a small 1/2" run (ish) on the outside of the metal tine, towards the end.  This can be quite thin, 1/32" layer.  The purpose of this is to every so little, push the tine in, so it no longer is aligned with the tolerance-play gap formed between the bolt-carrier and the receiver rail.  So that now it just engages the face of the bolt-carrier.    Note this application is only effective where the tine part gets raised above the lower-receiver and into the channel-area of the upper.  So only 1/16" down the tine is needed - if that.  Don't apply to the contact-face of the tine that engages the face of the bolt-carrier, as that part will get impacted and I can't say if it will hold up long to that.
Step 4: Using clean toothpicks, scrape the face and top of the tine clear, and then with a clean toothpick, run it along the top of the tine at a 45 (or so) degree angle, which will put small angle on the JB weld that's applied along the vertical outside surface of the tine.   Do this for both tines.  This way as the bolt-stop tine gets raised by the empty mag engagement and contacts the upper receiver rail, it won't just stop, but push in a bit, which is all you need.  We're talking 1/64" is all it takes to eliminate this problem.
Step 5: let sit for at least 8 hours, then pull off the tape, reassemble, and make sure everything is running OK by hand action (i.e. make sure you don't screw up and JB weld something frozen somewhere)

Bravo Zulu.  Navy?

Been wanting an RDB tan 20" for years and finally got it in November.
I'm impressed enough that now I want a LI extended handguard for it and another RDB, but the Defender.
Lazy, you might be able to speed up the cycling with the lightweight BCG from the Survival (and possibly Defender).
Also, you could mimic the lightening turning if you're that handy.

ETA:
Once I get the Defender, I'd put my FDE 2.5X PA prism back on the 20 and its current red dot on the Defender.

I think I’m going to sell mine. It’s like that girl in college that was one of the guys. She was always good for some fun times, was easy to sit and look at, and felt good in the hands, but you know in the long run she’s going to fall apart and give someone AIDS.

I hate to be that guy since I was so optimistic, but I’ve spent too much time explaining to range officers why I’m beating my rifle against the table to fix it.

What types of failures were you experiencing that called for beating it against a table?

Charging handle is peening the catch. This was taken awhile ago and it’s gotten considerably worse. Now I can’t free it up without blunt force.

Attached File

Thanks for the heads up.  I hadn't considered that location to be a wear item at all.  And will take a closer look.  I imagine one could Dremmel-grind it clear - but annoying.

Here's what it looks like with the successful JB weld addition.  It looks thicker and sloppier in the photo than it really is.  It's all but invisible to the naked eye, if not looking for it in on a disassembled gun.  KelTec also reached back out to me, and said ship the gun back to them if I like; but I declined saying it's running fine now.  


Here's my latch for the charging handle.  I think someone said don't HK slap the RDB too much, or it'll cause wear - I guess there?  I have pushing almost 1000 rounds on this gun now, if you can believe it, and it looks fine to me.  I will say, I don't dry fire this gun, and as such don't do a lot of empty gun bolt release with a pulled back charging handle.  So my charging handle doesn't slam forward very often.  I do this partly because I suspect the RDB has over-strong hammer springs to compensate for teh long throw of the hammer to engage (to keep lock time down).  So with that, it probably whacks the firing pin rather hard, and so I don't dry-fire it any more than I have to.  Which also means I don't rack and release the bolt very much.  For the most part, my charging gets run at the start of the day, and that's about it, unless there's a bolt hangup.



On other notes, I put at drop of blue nail-polish on the gas system at position max (0).  And I'm running a cheap $25 USB charged flashlight/green laser; though haven't given that a work-out yet on this gun.

I ground the burr off before unfortunately. It was pretty soft and the steel on the latch just makes itself a new home all over again. Heard grumbling of Keltecs warranty suffering now that Chad left for Century Arms so might wait til things seem a bit more optimistic.

Then again it could be a nice trade in on on a Tavor or VHS. Need to drink on it.

Do you have lithium batteries in that cheap flashlight?  Is the best place thermally for cheap lithium batteries directly above the gas block?  

Oh indeed you may well be right about that.   But for $25, let's find out - SCIENCE!!

Oh, I'm game - it's your rifle, your vehicle, and your house.  Maybe worth more than $25, but I presume you got a helluva deal on a heated doghouse & a gocart.  

More seriously, keep an eye on it - would suck if you're driving back from the range and you notice smoke coming from the back of the vehicle.  Or had a fire that evening in the garage.

Mind, I'm a luddite.  I think lithium batteries should be banned from commercial passenger air travel completely, you should have to FedEx your phone & laptop to your hotel before your flight.

Oh, that.  Naw, the battery size in this is too small to release enough energy to really light anything off; the heat dissipation rate for the volume of heat generation is unlikely to really light anything on fire - it's a tiny battery, for a tiny device.  Also, Lithium technology is now on the Li-Fe tech which doesn't really do that anymore.

For $25 it's not a Lithium Ion flammable?

Remeasured throat at ~850 rounds now = 2.497.  So about 0.01" growth.  Borescoped the barrel as well.  Looks good.   I can see some of the machine radial machine marks, which are radial.  This is typical to what I see when I borescope a PSA BBL, and just like a PSA BBL, they take a few hundred to 1000 rounds or so and start to go from OK accuracy, to better accuracy, and I think this one is too.  Will update with more detailed performance data as time allows (will be a few days).  As a hint though, results were interesting, with some rounds it HATED at first, it actually is shooting pretty good now.  Which is interesting.

Yeah some barrels take a while to settle in.

Hand lapping or fire lapping would probably have good results on a barrel like that.

1/28/2024 update - range outing accuracy and zero testing for preparing a ballistic table for the gun: 140 rounds fired. No failures - aside from a couple anticipated jams while doing gas adjustment for setting optimizing.

Also, verify that JB weld spot on bolt-stop arm to move it away from the rail a tiny bit, worked.  And it did, the gun no longer locks up on bolt lock, and the bolt release works well now.

Below is performance accuracy and impacts of different ammo at 200 yards.


With this, my nominal practice is to make a gun-specific ballistic table; with the gun zero'd at 200 yards with the 55 ball, and then the sights left at that setting, and note what zero that means for all the other ammo, and perpare the ballistic table for the gun at and left at the zero for the 55 ball.  Which i'll work on now and post below if I get to it any time soon.

A couple items of note - the overall accuracy is about expected at 2 -2.5 MOA nominal with ammo it's OK with.  Not great, but serviceable.  Of interest a couple trends:
-There really was no trend with bullet weight and accuracy performance.  Light or heavy on in the middle, nominally was about the same.
-POI at 200 yards very much did shift with weight, with lights going high, and heavies going low (FWIW, opposite of AUG; though I can't say what that means or why).
-Accuracy with ammo it had hated, has gotten better.  With M855 giving 2.5 MOA, and the 75 gr Hornady ammo (over IMR8208) it really quite liked.  Don't read too much into the 73 and 77 gr ammo accuracy, as those are American Reloading pulled bullets, and rough-life treated bullets at that - they don't shoot that great in any gun.
measured throat erosion after cleaning, which is noted a couple of posts above.
-Older lot of 55ball, and I guess with a conservative charge that day or something, as it clocked a bit slow IMHO.

Also updated the gas settings table.

Total round count: 820 rounds fired through this rifle so far.

I'm pretty much set to pick one of these up soon, a standard 20" in OD. Main reason is my current obsession with ambi all the things. And the RDB is better than damn near anything else out there in that regard on top of just being an overall cool design IMO. My only hangup being that charging handle. Why do companies always seem like they're all on board with the whole full-ambi thing and then always leave that one thing, one control where they just go "Meh, reversible is just as good as ambi right?" No, no it's not, why do they do this? You get it 90% of the way and then just say fuck it.

Anyway, with my autistic screeching out of the way.

Has there been any news on someone making a full-ambi charging handle for these?

Main issue I see is that both the standard folding charging handle and the non-folding Defender version use a latch to lock to the gasblock to keep them forward and not reciprocating around when they're not supposed to. The latch is integrated into the handle itself and unlocks by you pulling back on the handle. So you can't just make a simple copy of the factory design but with a factory handle on both sides, because then it locks on both sides and you can only practically unlock one of them at a time when operating your charging handle. It would need some sort of lever trickery to make it so that when you pull back on one, it forces the other side to unlock as well. And it looks like it's pretty tight on space in there to do much of that.
Or replace the whole latch design with a simple return spring like on an UZI charging handle. But that probably wouldn't be secure enough if you have the bolt/piston extension thing reciprocating inside the whole cocking tube. Would be easy for the two to bind together due to dirt, rust, shitty luck and now you have a surprise reciprocating charging handle.

Are there any closeup shots of the M43 prototype's charging handle? Looks like it's just a simple solid handle (presumably) welded solid to the cocking tube and doesn't use the same latch design as the RDB. Wonder how they handled this issue on that rifle. (possibly not well enough if it ended up getting changed on the production model)

Honsetly seems like it'd be easier to just make it a reciprocating charging handle. Then it's easy peasy to make it full-ambi and avoid all this locking, latching headache. It stays tucked up above the handguard and folded away when not in use. Who gives damn if it reciprocates? AKs have reciprocating charging handles, they've been doing just fine for the last 80 years. Additionally since you have no other direct access to the bolt or any way to see where it may happen to be hung up in it's cycle, having the charging handle's position immediately indicate "Hey your bolt isn't fully closed, probably a jam, fix it." seems kind of handy.
Perhaps I'm getting too hung up on the whole non-reciprocating part of it, mostly because all the Tier 0 gun-bros tell me that if my charging handle moves on it's own, it's my funeral.

Stribog has a "non-reciprocating" handle that doesn't lock.  So sometimes oit can move around during recoil, since it's just free and not attached to anything.  Irrelevant and no big deal.

So maybe you can just disable the latching system entirely?

The Beretta Cx4 has a pretty nice reversible charging handle that you can throw another one in on the other side & make it ambi.  I need to get the boy another one.

Found this old video of some dudes shooting an M43:

KelTec M43

(sorry not YouTube so no embed, but whatever, why give YT the clicks?)

When firing, I could see just enough to tell that it's a reciprocating handle. So I guess KelTec didn't address that on the M43. Like me, they said "fuck it, just make it reciprocate."



I suppose that's also an option. Or do kind of like the ball-detent lockup on the aftermarket HB charging handle for the earlier Stribogs. Just cut a little angle to the locking surface of the latch so it doesn't completely "lock" against the gasblock. It just sort of.....detents? against it to just encourage the handle to stay forward. That'd be a simple solution without any permanent mods to the rest of the rifle besides the charging handle assembly.

Here's my ballistic table for the RDB.  It's tricky, because the 3 heavies shoot so much lower than the 55 ball ammo that they never arc up high enough for them to overlap into the sights.   They impact about 9 inches low at 200 yards.  Though conveniently that corresponds to the first dot. In the three dot drop compensator in the scope.



(Ineed to rerun the M855 column, those numbers look off.  Wrong BC?)

And here is the reticle overlay for 55 ball, for the PA 2.5x scope I use

2/2/2024 Update - 50 rounds fired at a gong-range
Visited a gong-range last weekend.  RDB wasn't the focus of that trip (6.5's going long range was), but wanted to hit every single piece of steel this day - so brought the 5.56 RDB with a 50 round box of 75 gr match ammo, to take out all the 250-450 yard gongs.  



Put a cheap Amazon bipod on it that came with a picatinny quick-release system.  Kind of love it.  It even has tilt-capability.  For $28, really kind of love it.  Ran prone, on a sheet and drop pad I brought with me, and ran 20 round magazines.  though I think it could run 30's just fine prone.



I messed up and doubled my 1/2 MOA click math twice somehow.  So rather than putting 9 clicks for 4.5 MOA elevation to center my 75 gr loads in this scope (see prior post, where it notes the heavies all impact about 4.5 MOA lower than 55's on a 200 yard zero); I somehow goofed in my head and put 18 clicks on.  Which would explain why the impacts seemed pretty darned high on the steel, and I had to hold low on most shots!  A user error item.



Hit rate was decent, with some gongs 1-shot hits (the big ones), after figuring all that out.  And some gongs taking a good number more (the tiny ones).  There were nominally 4 gongs / distance, going in 50 yard steps from 250 to 800 yards, and  this rifle was used out to 450 yards, when I ran out of ammo.  Average total hit rate was around 50%, which isn't great, but worked.  Scope is just 2.5X.  And here's a cell-phone shot through the lens, which of course doesn't really capture the clarity so well, but gives an idea on the magnification level and what's being asked of the scope, gun, and ammo.  Around a 10MPH side-wind today.



Had fun. Gun ran very well.  No bolt-lock issues.  Accuracy was OK, but I probably should do a more dedicated RDB revisit and take it out to 600 yards.


Total round count: 870 rounds fired through this rifle so far.

What does your weigh in that configuration?

Just read the whole thread.

It seems this rifle really could developed further. Since Smith and Ruger are known to copy and improve KT designs, this would be a nice one to do.

Lazy, what clear mags are you using in that pic?

ETS

Their 30 round AR mags are quite underappreciated.

I want to say it was 7.9 pounds loaded. Will try and charge the scale up tomorrow to verify.

I shimmed my RDB-20's handguard to remove the fore-aft and up-down slop.
No idea if it made things better or worse, but it feels better.
Will probably end up with the Lucky Irishman extended handguard at some point.
I have some hope that the Arisaka M-Lok offset picatinny mount would be close enough to zero an MBUS, greatly extending the sight radius.
It's too bad LI doesn't offer a top rail that matches the height if the factory rail...

Took RDB out this weekend and shot at 500 yards.

Performance was meh, on accuracy, with nest results a 500 yards from thr 75 gr ammo, and dialing in the scope.  Trying to do holdover wasn't nearly as good.  Conditions were NASTY wIth 22 mile an hour cold cold winds.  I didnt really want to be there, it was that unpleasant (very rare for me to say that about a shooting day!!) Which hurt things.  But all the shots impacted in the black at 500, so serviceable.

Then did some 200 yard mag dumps later, and just had a blast.  Very pleasant gun.  I do now like it better than my AUG.  It never jams either.




Run a quick detach bipod


MK318MOD1



I know these guns supposedly can get hot - but I have yet tonrealy heat it up proper like.

It is remarkable how pleasant and recoil free this gun is when the gas system is tuned just so.  I tend to run it a click or 2 past that, for assured reliability.  But you can adjust it down to just barely cycling, and it's like shooting a .22 when you do.  A friend shot it Saturday.  Sunday he sends me texts asking where to buy one.  He too was an AUG owner, and he too likes the RDB better.

As a reloader, one occasional experience will be a blown primer, from brass with a worn primer cavity.  In the AR15 platform, that can typically end up in the trigger and jam the rifle up.  I don't encounter this often at all - quite rare - but it does happen over enough rounds.

One little noticed feature and appeal to the RDB is the casing doesn't tilt away and allow a loose primer to separate until over the down direction ejection chute.  It would appear a blown primer is less likely to end up bouncing around the internals of the gun and result in problems in an RDB, compared to most other guns.  Indeed, other side eject bullpups like Tevor and AUG also are less likely to have trigger issues as well.  But the blown primer could still end up in the mag well area and action and cause cycle close problems.  Where in the RDB, there is nothing below where the casing finally tilts away from the bolt face and exposes the lose primer.  It will simply gravity fall down the well.

Or at least, that's how it looks.  An under-praised advantage unique to the RDB - I think so, at least.

2/24/2024 update:  Fired 60 rounds on the gong range.  No failures of any kind

Set up on a pleasant day and used the 1/2 MOA clicks on the scope.  2.5X fixed power scope, running the 75 gr Hornady HPBT at 2790 fps.

100 yard zero = +7 clicks (so 3.5 MOA).  This would be for a scope set for a 200 yard zero with 55 ball)
250 yard = +12 clicks for 1st shot hit  (This would be +12 clicks TOTAL  for a scope set for a 200 yard zero with 55 ball, to impact at 250 yards with this 75 gr ammo)
300 = +15 clicks (total) for 1st shot hit on the gong at 300 yards
350 = +19 clicks
400 = +23 clicks
450 =+28 clicks
500= +32 clicks (per calculator) but came out +31 clicks actual
550= +38 clicks (per calculator) but came out to+37 actual

Couldn't tell if I was able to first shot connect at 600 yards.  The steel was pretty chewed up and at that distance so wasn't so easy to see if an impact hit via the spotting scope.  And at that distance the steel didn't react or gong so loud.   So might have hit, but maybe not.   And then the range officers gave me the stink-eye for having such a low power scope shooting .223, and asked me not to go out any farther.    Which TBH, is mostly fine - as I don't know if the gun would have done much better much farther nor been so easy to see if impacting.

Switched back to 55 gr ammo and adjusted scope back to it's zero.  Confirmed zero and pinged some steel out to a few hundred yards using the scope drops, which were spot on.

No failures of any kind.  The gun is a sweetheart to shoot from the prone position.  I also brought my AUG, which I intend to now give a thorough cleaning to, as it might be a while before I shoot it again. The RDB is just a pleasant and enjoyable gun to me.
Total round count:  1030

3/6/24 update  - fired 30 rounds with no failures.

Running gas at -3 clicks and 55 ball.  Ran 30 rounds to zero the laser at 15 yards.  It's a cheap laser so moves when touched to turn on, but returns to zero when stop touching it.  Ran 6 X 5 round magazines.  Zeroed with first mag.  Mag dumped the remainder onto 50 yard steel with main sight.  Then zero check again at 15, which was still good.

Gun continues to be a mild sweetheart to shoot.  Friend had hisn10.5" SBR AR.  The RDB was shorter and had a milder recoil, and about 600 fos more velocity per the Garmin.

This is a cool gun.  Didn't bother cleaning it.

Total round count: 1060

Installed the TALON stick on grips over the pistol grip.  nice feel, but really, I just wanted to cover up the hideous KelTec checkering.  Did the hair-dryer thing to soften/melt/secure the adhesive.  

Also adjusted the quick-release pop-on bipod to install a notch that lets me run it a bit lower when desired.  $25 for that bipod is a steal - I bought 4 now.  It's basically better version than the $100 MapPul version.


(blottlet SN because not every AI auto-scanning the internets is your friend)

3/10/2024 update:  Fired 87 rounds in a 50yard action bay.  no failures.
Did a zero-check on the cheap Amazon laser/light, and then cooked it with 2 mags of rapid-fire, and then a zero recheck - was mostly the goal.  Only item of note is I brought some 64 gr ammo, that impacts lower than my baseline zero, so some low-impacts on target, but otherwise no issues.  Ran gas at -3 (default for my 55 ball), for a couple shots, noted it was snappy, took it to -5 which is what I should have set it for this ammo to begin with, and it ran soft and smooth.  In truth, one could aurgue snappy was better, as an overgassed RDB snaps back to target faster than one soft-gassed.  But oh well, it's easier on the gun this way.

Todays field of fire 50 yards:


Configured for some bench testing with the QD bipod.


Cheap amazon green laser daylight at 15 yards


At 25 yards (10x camera shot; bottom of target)


At 50 yards (10x camera shot)  Photo makes it better than it really was, and it was kind of hard to instantly see with bare eye at 50, unless it's moving.


Though one thing I've learned with lasers, even bright green ones, is daylight usage is very spotty.  Even if you can see it on target, at night they are AMAZING because you can see it where-ever it is, bring it to bear on target very very quickly at night.  Whereas day usage with a laser basically requires you to be on target already, before you can really see it.  



Here's the gun after putting on a camera/light rig (I'll go check and see if the video's came through)


And here's the laser impact point after running it and heating it up good.   It moved some, but a lot less than my AUG does under similar, and decent enough for purpose.  Don't know if I'll keep it at 15, or move the zero out to 20 or 25 yards - I very well might do that.

Total round count:  1117 rounds

Have you thought about putting on a linear comp or flash can?

No.  Perhaps your chance to educate me, but my rather opinionated bias on such is that those products don't have my interest.  I compare all muzzle devices to the A2 FH, who's dimensions I consider maximum acceptable dimension addition to the end of a barrel.  And so opine perhaps too much at the knee-jerk level; that those devices add significant weight and length for features I personally don't really value.  In general, if I'm willing to go longer than A2 FH dimensions for a reduction in blast and flash, I'll just add that length in barrel, for reduction and blast and flash - and get the velocity improvement from it too; while still running a shorter muzzle device.  I'm finding the BCM unit (which is A2 dimensioned), on the 17" doesn't give an unpleasant blast of flash at all.  (though it be SPARKY on a 10.5" )

Interestingly, I find the AUG far more blasty than the RDB; even though the AUG has an 18" BBL.  I guess a combo of the much more pronounced AUG recoil (by a lot) and the gas venting from the goofy AUG gas system (where the theory is to drill a huge hole in the barrel into the gas system, bleed all of that, and then adjust how much of that is vented away).  The RDB is apparently similar, in that it too is adjusted by how much of the gas is adjusted in the vent away, but it's tapped much MUCH further down the BBL - at almost a Garand's tap location;  and so there is no noticeable blast from the much lower pressure gas system of the RDB.  It's smooth and very pleasant, but does require gas setting adjustment when notably changing ammo type.  Which isn't that big of a deal, just something to be aware of if running mixed ammo.

There are some very small flash cans that basically mimic the external A1/A2 flash hider shape length but help to channel the expanding gasses downrange more than a flash hider w/ side ports.

Flash cans are typically aluminum so can add minimal mass to the end of a barrel, tend to be pretty inexpensive, and since made of aluminum, are easily shortened to your preference.

Linear compensators are typically steel and can add considerable mass, but may be able to produce less flash than a flash can, as there are internal baffles whereas a flash can is typically just an open can.

The heaviest linear compensators, such as the Flaming Pig, are basically ATF approved single baffle steel suppressors that can boost gas pressure in short barrel AR & AK pistols.

4/14/2024 update:  Fired 20 rounds  - no issues.
Today's focus was on practicing shooting from shooting sticks.  



For context on why:
These are used while hunting at times, in open field.  In particular, I typically hunt with a 2-4 man night hog-hunting group (not often, maybe 1-2x/yr) where we do a fire-countdown, while open field and within about 50 yards of the target hogs.  Using thermals.  I run a 6.5 Grendel that serves me well (would LOVE to find a 6.5G bullpup).  Typical practice is we travers at night using glow-tape on the back of our hats, and point-man has a hand-held thermal.  And we walk with rifle vertical hung 1-point-sling on the right, and left-hand is the shooting stick horizontally.  And that's how we travers.  Upon sighting, shooting sticks are quickly planted and right arm brings gun up into the stick and on target - eye into eye-peace (to seal in the light), and the thermal turned on.  Shooting sticks are to keep the guns steady to allow a uniform fire on the countdown.  That's the theory at least, doesn't always work.
[edit, here's a typical gear-out for it]
https://i.postimg.cc/tgrsMCZb/20240406_202205.jpg

Back to RDB focus of the thread - I find shooting from shooting sticks not nearly as stable as you might think, and in fact I still don't think I've mastered it that well.  There's an art to this I need to figure out better. It's easy to swing off target still.   So, off to the range I go.  Todays focus was 20 rounds fired at the steel rams at 100 yards using this practice.  Each shot being a new and deliberate shot from a gun brought up to bear, at firing that one shot at my own pace.  

I hate to say it, but my hit rate on those ~4x6" Rams(?) you can see hanging above the paper targets at 100 yards, was not 100%.  Maybe 70%.. maybe less.  That's not the gun, that's me and trying to master shooting sticks.  And I was curious if the central balance of the RDB bullpup would help.  Short answer is - not really.

Total round count:  1137 rounds