The solution to the bolt failing to lock back with NDZ's SBR lever installed is very simple: clip two turns from the Bolt Latch spring! It should be noted that this is exactly the same fix for bolt lock back failure that has been recommended almost from the introduction of the 15-22.

For the past three weeks I have been testing (with NDZ's knowledge) both the original SBR lever and the new, lighter lever. Here are the results:

Unmodified Spring:

25-round magazines - occasional failure without any lever attached.
10-round short magazines - no failures.

With original lever - 95 percent failure with long magazines.
With original lever - no failures with short magazines.

With new lever - 50 percent failure with long magazines
With new lever - no failures with short magazines.

Two turns clipped off Bolt Latch spring:

Original lever - no failures with long magazines.
Original lever - no failures with short magazines.

New lever - no failures with long magazines.
New lever - no failures with short magazines.

(it should be noted that the springs in the short magazines are considerably stronger than the ones in the long magazines)

Test Conditions:

Five (5) 10-round short magazines, 8 months old. Five (5) rounds per magazine, each one reloaded five (5) times for each test.

Four (4) 25-round magazines, 8 months old and four (4) two weeks old. Each magazine loaded with five (5) rounds and reloaded a minimum of ten (10) times for each test.

These tests and the results have been shared with the folks at NDZ, both via eMail and in person (they are only about 20 minutes from me).

If you are having trouble with either the original or new lever, simply clip two turns from the Bolt Latch spring.

sometime this week ill test my version 2 lever with the uncut spring then go from there.

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od: xd9 3"&4", 15-22, 1911 .22

I'm anxious to know how you fare with the test. The guys at NDZ will want to know, too. They really are a nice bunch.

I wonder if clipping one coil would still work. I have to wonder if clipping coils is going to have any unintended negative side effects.

1 - don't know. All previous recommendations say two.

2 - Well, after well over 800 rounds on Friday and today, I haven't found any. I can't envision what else would affected except the locking back of the bolt. That's the only thing the bolt latch does. If one doesn't care about locking back the bolt, the whole latch and spring could be removed and everything else would function just fine.

All of my testing showed that one coil is not enough and 2 is just right. If you take off three or more the bolt release can rattle around and possibly get in the way of the bolt because it won't have tension to keep it in the "out of the way" state.
The lighter spring tension of the long mags sometimes does not have enough power to overcome the bolt release spring. So we reduce the bolt release spring pressure by shortening it.

__________________
Buy cheap, pay twice.

I find it interesting that the springs in the short magazines are so noticeably stronger than the ones in the long magazines. I think the whole problem rests with the weaker springs.

Even without modifying the spring, the short magazines were 100 percent lock back with both the original and lighter levers.

I think major hit the nail on the head. Seems as if 90% of all malfunctions encountered on the rifle for me at least are directly attributed to the weak mag spring on 25rd mags. Zero malfunctions with shorty mags. Even with old dirty ammo.

It'a also interesting to note that the short magazines are less than half the length of the long ones and yet the springs are only 1/4th shorter.

BTW, stretching the springs doesn't do anything. As soon as you load 25 rounds into the magazine, the springs revert to their original length.

I'm of the opinion that S&W needs to rethink both the long mag spring and the bolt release spring.

Smith wouldn't even need to change the springs. They can put a slightly longer core pin in the mold to deepen the hole. That would have the same effect as shortening the spring.

__________________
Buy cheap, pay twice.

I hadn't thought of that.

Now someone is going to try to drill the hole "just a tad deeper".

I just did my grandson's rifle and realized I put the little detent on the wrong end of the spring - to the inside.

3/4 mags didnt lock back with an uncut spring.

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od: xd9 3"&4", 15-22, 1911 .22

I'm glad it's a easy fix. I only had to take off one coil. I wonder how many people have had to cut the spring.

Sent from my Galaxy Nexus using Tapatalk 2

Since installing my NDZ extended bolt release I've been having issues with the bolt not lock back after the last round fired....i'm going to try this fix, I need a remedy...it's annoying to have to reach up to recharge the rifle.

THANK YOU for taking time to do this test and for sharing the results with us!!

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Maker of The TALON Video Mount

Followup ...

My grandson and I spent the morning at the range (the kid LOVES to burn up grandpa's ammo!) and we put a little over 800 rounds through 11 25-round magazines. Not a single failure of the bolt to lock back after the last round.

As far as I am concerned, the fix is in!!!

Every one that wants the SBR to work.

This is awesome news. I had the original sbr and returned it. Looks like I will be ordering a gen 2 sbr today.

The guys at NDZ put in a lot of time and effort (money) into trying to solve a problem that really wasn't their problem in the first place. As TactiCool and others found out, S&W made the spring too strong in the first place. The failure to lock back existed long before the SBR came on the scene. I simply don't believe the people who put MagPul's BAD on their 15-22s have not had exactly the same problem us SBR folks have had.

Personally, I like the original better, but I would be more than happy with the gen 2 version.

800 rounds.... But didya hit anything?

Hey Guys thanks for all the nice comments... We NDZ, are Committed to bringing you the best quality products that we can. Some times we run into some snags like this one. But We did not give up and Like Majorlk said I new early on that 2 things would fix the problem A lighter Bolt catch spring or heavier Mag springs.. But we went back to the drawing board and cut the weight in half trying to fix the issue so that no one had to worry about cutting springs or altering your stock gun. Sadly there were still some issues because the problem was a combination of 3 things First the heavier bolt catch spring was an issue on stock guns using 25 round mags. Second, is the weaker springs found in 25 round mags, and third is a Timing matter in that the 22 caliber round being a smaller round and not having the gas blow back that larger .223, round has causes a timing issue. So add all those things up and you get the Failure.. With that said like Majorlk has mentioned Clipping the bolt spring will fix it.

Currently we are in the process of sourcing a lighter spring and if so we will include it with all the new SBR sales so that you will not have to cut your stock spring. This way you can put the stock spring back in if you wish.

On a Side note If we source these springs I will post on here and I will send a spring to anyone with an SBR that wants one just contact us.

Thank you all for standing behind us and look for new things to come from NDZPerformance !

A Special Thanks to Majorlk for all your Help with this.

You're supposed to hit things???????

We have some small swinging targets, a spring loaded knock down, bowling pins, and of course, a selection of vicious attack rocks.

My pleasure, guys. As I said at the shop ... any excuse to go shooting.

Now that's what I call a quality company that really cares about customer service!

I have found that the vendors who are members of this forum all have great customer service.

After that last post by NDZ, I will definitely buy the SBR lever from them when they include the needed shorter spring as I was skeptical about cutting mine just in case I didn't like the lever. Now there is no risk whatsoever. Great customer service on their part!

We are still trying to Source a Spring no luck yet but we are on it.

There's no risk cutting two turns off the spring. It still functions 100 percent, with or without the lever installed.

Just a reminder that this has been the recommended solution for failures of the bolt to lock back since shortly after the 15-22 was first introduced.

The springs are only $2.00 so the risk is very small.

__________________
Buy cheap, pay twice.

Are there any images/videos of the spring mod?

Don't know, but it's not difficult.

- make sure gun is empty with nothing in the chamber.
- lay gun with bolt latch side up.
- with a small drift punch and small hammer, drift the roll pin (from either side) out until you can pull the bolt latch out of the slot. It's not necessary to take the pin completely out.
- remove spring.
- cut two turns off the spring.
- Re-insert spring and the detent.
- reinsert bolt latch.
- drift the pin back in position.

It took longer to write these instructions than it does to do the mod.

^can you make a youtube video?

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od: xd9 3"&4", 15-22, 1911 .22

I don't do youtube.

There are pictures in the original thread.
I will see if I can put them here again.
Like Majorlk wrote, it takes about as long to do the mod as it takes to read the instructions.

Attached Images

	Clipped Bolt Hold Spring 1.jpg (58.8 KB, 110 views)
	Clipped Bolt Hold Spring 2.jpg (75.4 KB, 98 views)

__________________
Buy cheap, pay twice.

Didn't know that. You learn something everyday, I guess. I thought it would have affected it in some way if I took the lever off the bolt release and that the modification was supposed to be only made if the lever was installed.

Hate to revive an old thread but I finally got around to putting an order in for the SBR a couple weeks ago. Got it in the mail last week, installed it, and cut two turns of the bolt latch spring as mentioned above. Went out to the range last Friday night and did about 30 mag changes only loading about 5 rounds per mag, with 3 different 25 round mags (my original one and 2 new ones). The bolt locked back after the last round every single time using Walmart Federal 550 Bulk.

Really happy with it as I have had my BAD Lever on my Colt 6720 for a while now and always wanted to put one on the 15-22 as well. Thanks to NDZ for making a great product!

Been waiting on my SBR for like 10 days.. should be this week as they got backed up.

Now, so far I have had zero issues across 5 mags with the bolt locking back with the stock spring. So, my plan is to leave the spring stock and shoot with the newer lighter SBR on it and if needed, I will cut it then.

Thanks for the guys that did the research on this.

Thanks guys and sorry for the delay... We have been getting our buts kicked so to speak... Hope everyone is well !

I just received my SBR and carefully clipped two coils off of the spring, and installed after reading all of the posts very carefully. I cant decide whether the play in the bolt release is just wildly exaggerated all the way down at the finger release, or i cut off too much of the spring.

i dont have any experience with AR's or the B.A.D. lever so i cant compare, but yeesh the thing almost dangles. (yes everything is screwed down tight). i have not been able to take it shooting yet to try it out for functionality.

I was hoping that NDZ would have sourced a spring to include in the kit by now.

i know it is probably a $2 replacement spring, but i really dont think i could have over-cut it since i can count

could s&w have corrected this factory spring and i just made it even shorter? does the SBR naturally flop about?
dont get me wrong, the NDZ SBR is perfectly machined and as advertised. the gripe is with the ping pong paddle flop that travels and escalates all the way through to the end of the lever. its almost as if i need to put a shim in there to hold it against the lower more securely. but then you run the risk of it not performing properly.

Don't fret. Anytime you extend a lever as much as happens with the SBR, any movement is magnified. After a few times, you'll never notice it.


Not worth the effort on their part.

I have put them on three 15-22s and none "flop about". There is some movement. That's normal.

You are worrying about nothing. There is lateral movement in the paddle from the factory. You just don't notice it because you don't move it sideways in normal use. Quit wiggling the SBR and just let it hang in position and enjoy having the bolt release at your trigger fingertip.

thanks for the quick reply. sounds like everything is ship-shape then. cant wait to play!
sidenote- interestingly enough, my NBZ charging handle+latch didnt ship with the SBR and didnt arrive today either. they must be backed up. BIG thanks to all the fellas here on the board for all of the info on both the SBR and charging handle. i was halfway through an order form for the Plinker Tactical when i figured i better do my homework. im sure i made the right choice here.

cheers

Both of my two grandson's 15-22s have the NDZ charging handle and latches, as well as the oversize mag release button and the SBR.

I live about 25 minutes from the NDZ shop.

I already bought the SBR Lever from NDZ and can't wait to test it. Didn't know about the mod that has to be done but it doesn't seem like a problem.
I'll post feedback and pics as soon as i mount and test it. In couple of weeks as im finnally in Holidays...
Cheers

Rod


Sent from my iPad using Tapatalk HD

Big fan of NDZ , these guys are way cool and the way they respond to you is great. I want to thank everyone for all the collabrative information . Im going to be ordering my own SBR soon and feel confident in installing it.

Update:
So i couldn't get over the slack and play at the end of the SBR. Again, this has *nothing* to do with the NDZ product itself. The stock bolt release has a little play in it that you will never notice until you attach the SBR.

I ended up using a paper hole punch to punch out two circles of thin, black, flexible plastic. Then used the bolt release pin itself to punch a hole in the middle of them. I used them as shims on either side of the ping-pong paddle. Reinsert the pin and you have yourself a rock solid SBR.

I just wish NDZ kept the original "heavyweight" design

Interesting. I have not paid any particular attention to the problem. Maybe yours has more "slack" in the latch lever, but a nice solution to yours.

I prefer the older style, too. But in testing both of them for NDZ the almost double weight of the old style presents lock back problems, even with the clipped coil. My post on 24 SEP 1012 details this.