SBI Lynx 180B Lower Info and Feedback, for WK, MCR, and AR180B

the radium king said:
i think you're not getting a lot of uptake to your questions as this is a thread about lowers - no gas blocks here?

however, to sort of answer your question, the 180 clone market has yet to standardize and there is a lot of variation; the wk/mcr is a piston gun with a proprietary and relatively tall gas block (read: only some ar handguards fit) the tna is an improved wk, the rwa is also proprietary but somewhat lower (but takes a proprietary handguard). wk/msc/tna are carbine-length with rifle-length available aftermarket from tna, while the rwa is mid-length. the jard is a di gun like an ar and *i think* takes ar gas blocks. all take ar barrels but make sure your barrel profile is such that it fits 0.75" gas block (except i guess the jard where you can draw from the ar aftermarket). there was an adjustable gas block for the wk/mcr/tna available however it's off the market (but google and making your own adjustable gas block only requires grade 9 shop class - drill a hole, tap the hole, install set screw). there are other uppers enroute but vapourware currently.
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Good summary.

True North Arms developed the initial aftermarket adjustable WK/MCR gas block. They have recently pulled it from sale, as they wish to refine its design, and will again offer it for sale once they've completed their alterations.

The Jard indeed uses an AR gas block (optionally adjustable) and gas tube, impinging gas from the tube directly against a Stoner-style pseudo piston BCG and bolt against a 180 style recoil recovery system. SBI is introducing a direct impingement BCG they say works best with their upcoming upper, but they say will also work with the WK and MCR. If this works out, it will allow the same re-use of AR-15 adjustable gas blocks and gas tubes, eliminating the need for a 180 piston compatible GB.

The upcoming RS18 gas block may or may not work with the other 180s; it is unknown, as it is being refined before further release. Suggestions from forum members when evaluating third party testing of a beta version of the rifle has resulted in them crafting the GB to use a dimple that will be added to the R18's barrel to keep the GB indexed. 180 GBs have been known to have their non-thread lockered fasteners loosen under use (as previous 180s have been over-gassed to eat garbage ammo and the resulting very heavy GB impact loosens the threads), causing the GB to rotate out of alignment, which can cause stress on and eventually snap the piston op rod. It is unknown if the dimpling would have to be reproduced on other 180 platforms for the RS18 GB to be used with them, or if the piston circumference is even close enough between the R18 and other 180s for the RS18 to work with the WK or MCRs piston.
 
:dI have an used IBI
HB on the way and I’m not sure if it’s .750 or .836.
That’s what I meant by different sizes.

I’m planning on removing some matarial , in front of the GB towards the muzzle but I guess I could remove matarial from the GB journal too.

I’m just not clear on 180 GBs and HGs
 
if 0.75 then you are good to go. if larger then either turn your barrel or jard (or wait for one of the others to come to market as per ustauk). i *think* the ibi HB profile is 0.75.

re handguards, again depends on height and how mounted. if going with the taller wk/tna/mcr then check the tna website; they have some inexpensive chineseum units that are guaranteed to fit, and also provide dimensions if you decide to hunt for your own. also several specific threads on this forum on the subject. if rwa then can only buy from rwa. if jard then i think anything will work, but not sure if the jard will work with your lower?

45C said:
:dI have an used IBI
HB on the way and I’m not sure if it’s .750 or .836.
That’s what I meant by different sizes.

I’m planning on removing some matarial , in front of the GB towards the muzzle but I guess I could remove matarial from the GB journal too.

I’m just not clear on 180 GBs and HGs
Click to expand...
 
the radium king said:
if 0.75 then you are good to go. if larger then either turn your barrel or jard (or wait for one of the others to come to market as per ustauk). i *think* the ibi HB profile is 0.75.

re handguards, again depends on height and how mounted. if going with the taller wk/tna/mcr then check the tna website; they have some inexpensive chineseum units that are guaranteed to fit, and also provide dimensions if you decide to hunt for your own. also several specific threads on this forum on the subject. if rwa then can only buy from rwa. if jard then i think anything will work, but not sure if the jard will work with your lower?
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The Jard upper works with no 180 Canadian lower, as it has the blind buffer tube socket included in the upper. It actually breaks down in a similar manner to the SBI LPC straight pull modular (takes AR parts) rifle.
 
the radium king said:
if 0.75 then you are good to go. if larger then either turn your barrel or jard (or wait for one of the others to come to market as per ustauk). i *think* the ibi HB profile is 0.75.

re handguards, again depends on height and how mounted. if going with the taller wk/tna/mcr then check the tna website; they have some inexpensive chineseum units that are guaranteed to fit, and also provide dimensions if you decide to hunt for your own. also several specific threads on this forum on the subject. if rwa then can only buy from rwa. if jard then i think anything will work, but not sure if the jard will work with your lower?
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I should be good then.
I also have a used WK takeoff handguard enroute.
All I need is an Upper.
 
45C said:
All I need is an Upper.
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i'd check with tna. they don't list their upper separately from their lower on the website, but i'm sure it's available. you get a lot of improvements for probably not much more than an off-the shelf or take-off wk or mcr upper. or wait to see what else comes to market. but it's kind of like buying a computer or tv - if you wait for the next best thing you'll never have a computer or a tv ...

presume your barrel is carbine length gas, yes?
 
the radium king said:
i'd check with tna. they don't list their upper separately from their lower on the website, but i'm sure it's available. you get a lot of improvements for probably not much more than an off-the shelf or take-off wk or mcr upper. or wait to see what else comes to market. but it's kind of like buying a computer or tv - if you wait for the next best thing you'll never have a computer or a tv ...

presume your barrel is carbine length gas, yes?
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Yes , I was told it’s carbine lenght.
Carbine lenght is causing issues right?
Would it help if I opened the hole in the barrel? Or would that make the issue worse
 
carbine length coupled with a big hole in the barrel sends a lot of gas into the gas system. good for cycling just about any kind of ammo, but can hammer the gun apart - 'over-gassed'. hence the aftermarket gas blocks that allow you to restrict the amount of gas to suit the ammo you are shooting. opening the gas port even more would probably make it worse. i think most barrel makers use smaller gas ports for the shorter gas systems.
 
the radium king said:
carbine length coupled with a big hole in the barrel sends a lot of gas into the gas system. good for cycling just about any kind of ammo, but can hammer the gun apart - 'over-gassed'. hence the aftermarket gas blocks that allow you to restrict the amount of gas to suit the ammo you are shooting. opening the gas port even more would probably make it worse. i think most barrel makers use smaller gas ports for the shorter gas systems.
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Got it, thanks.
I think a bit of blue locktight should keep it in place, at least it has on all the rest .
 
Yes I quoted myself... I ended up switching this out to the original style and putting this release in the lower of the donor rifle I bought. The gap just bugged me a bit. The last part to complete my lower was the trigger that Canada Post delivered to my door today on a Sunday, 3 days before it was said to be delivered :eek: So I'm off to the range tomorrow to try it out. Now I need to figure out what to do with a spare complete lower.

KBCL said:
Putting a lower together and figured someone might want to see a pic of the external bolt catch release installed. It's not ideal with the gap underneath but not bad either. It won't work if you flip it 180 degrees (well it will but you can't get the upper on) but it's way easier to manipulate with your thumb when its flipped 180. I haven't decided if I'm going to leave in installed or switch to the original style without the release.

i8r0cCT.jpg
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I had it out to the range and had feeding issues. The end of the bolt catch was hanging up sometimes and not letting the bolt forward so I compared the original without the external release to the ext. rel. that I had installed pictured in my previous post. The tip of the ext. rel. was bent differently and a bit smaller so I put it back in and cycled some snap caps. It was better but still hung up so I had to file down the tip a bit and it seemed to fix my issue.

Back at the range today and it cycled everything in the 3 different 5 round mags I have but would not feed anything from the 10 round mags I have. Everything worked great with snap caps so I suspect part of the issue is the Norinco copper washed steel case stuff I was using. The snap caps just feel much more slippery so I will pick up some brass cased stuff to try out.

Any advice on getting my pistol mags to feed?
Edit to add; The springs in the pistol mags are way stronger than in the other mags that are pinned to 5. Would this be a spot to look into? Sorry for the noob questions.

One other thing, I installed the external bolt release a little different and it's very easy to reach with my thumb and manipulate. I could probably shave 3/8-1/2" off the end and it would still be easy to use.

vinX3IE.jpg
 
I bought a complete WK in 7.62x39 new to put this together. It was unfired until I put it on the Lynx. I may put the original lower on just to try and eliminate the Lynx lower but I don't think that's the issue.
 
i would do the elimination process so that you are not chasing red herrings. for the pistol mags it could be frictions in the system (making the firearm non-functional when a stiff mag is used) which speak more to the upper being the issue (or wanting some oil) however given bolt catch issue it could also be tolerances between upper and lower (mags are finicky with that stuff) however that could also just be an issue with aftermarket bolt catches. lots of variables so take them out of the equation one by one.
 
Failure to feed issues are identical if not slightly worse with the KD lower and SBI lynx lower. Tried the same ammo and some brass cased stuff. No luck with the pistol mags and one of the 5 round mags that worked fine with the lynx, made the bolt need a little extra help with the KD lower.

I think I’ll send Kodiak an email but if anyone has any tips I would appreciate them.
Cheers!
 
yeah, was looking like an issue w the upper. either not enough gas (gas block misaligned) tight chamber (known issue) or something rough in the receiver i(or not enough lube) such that you're short stroking a bit. add a tight mag and it stops working.
 
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