Quick update on my ongoing saga to get a Just Right Carbine in .45 running properly. To recap:
- Got a JR in .45 back in April of '12
- Didn't run well, back to Epps for servicing in summer
- Still not running properly, spoke with JRC folks in NY in December and they shipped out a 'fix' kit that arrived last week
Why the hell am I still f'ing around with this?
- I really want an NR, modestly expensive .45 carbine that takes regular 'AR' furniture
- You might say - 'buddy just get a TD or KRISS in .45!', and in hind sight maybe you're right.
- I'm also irrationally invested in this now, so I'm going to continue on this path until it works or is destroyed.
So - the kit that arrived:
New heavier buffer, new magwell, new bumper(s) a buffer tube 'extension' as well as some locktite and an allen key.
Here's a comparison of the old magwell next to the new one:
New magwell furthest from the shot, you can see that the feed ramp is a bit beefier, and better sculpted than the original one.
With the magazine and a snap cap installed the difference becomes a little more pronounced:
New magwell on the left, it seats the magazine very nicely. Compared to the original it seats the magazine a bit more tightly, and doesn't allow for over-insertion the same way the original did. Also - I think the pic shows that it's a slightly less drastic ride to the feed ramp from the magazine.
On the buffer tube side of things, the new tube is longer and heavier than the one it shipped with. I guess this explains why the buffer tube extension is needed.
I weighed the new one, it comes in at around 10.5 oz according to this scale:
The old one was ~8.75 on this scale, so the new one has around a couple ounces on the old one.
The buffer tube extension:
Possibly the least elegant part of this kit. It's a piece that threads onto your existing buffer tube, and is meant to be thread locked and set in place with a set screw to your existing buffer tube. I have a UBR that expects to be right next to the receiver acting as the end plate and castle nut, which is not going to work with this fix.
I've got an LMT sopmod stock and conventional buffer tube that I'll switch to - but won't have access to it until next weekend. For now, I've put the UBR tube on, just so I can test the effectiveness of the fixes.
Before shooting:
The UBR is sitting loosely on the tube, just figured it might feel better than planting the tube itself into my shoulder. Inserting the magazine with the bolt forward felt harder than I remembered but it went in well. Racking it was difficult on the way back, but the bolt came forward and chambered around much more smoothly than before the changes.
First three shots:
The first three shots were silky smooth, and the perceived recoil was negligible. The heavier buffer seems to have made things a fair bit smoother!
And that, is all the good times that would be had with the JR yesterday.
Round 4:
The bolt came forward, unseated the round and got stuck. Touching the bolt handle it's clear that it had come loose. When I removed the magazine it came out freely, as did the round.
On inspection it appears the bolt handle was lightly making contact with the rear of the receiver.
There is what looks like a small metal shaving at the rear of the receiver, and the bolt handle is a write-off. I've got a couple spares.
I'm hoping that the failure today was as a result of me not having thoroughly enough 'locktite'd' the bolt hand into place. I don't think the UBR tube is any longer and a conventional carbine tube. I'm not sure if the bolt handle was loose because it wasn't fastened well enough to the bolt, or if it came loose from contact with the rear of the receiver.
I don't have my tools handy, so a further work on this will have to wait until next weekend. My plan is to:
- Disassemble, check out bolt and receiver if ok;
- Replace and locktite the crap out of the bolt handle
- Replace UBR with original buffer tube and stock that shipped with the JR
- Ensure that the bumpers included are sufficient to preclude contact of the bolt handle with the rear of the receiver
- Try, Try again...
What fun would it be if stuff just worked?
- Got a JR in .45 back in April of '12
- Didn't run well, back to Epps for servicing in summer
- Still not running properly, spoke with JRC folks in NY in December and they shipped out a 'fix' kit that arrived last week
Why the hell am I still f'ing around with this?
- I really want an NR, modestly expensive .45 carbine that takes regular 'AR' furniture
- You might say - 'buddy just get a TD or KRISS in .45!', and in hind sight maybe you're right.
- I'm also irrationally invested in this now, so I'm going to continue on this path until it works or is destroyed.
So - the kit that arrived:
New heavier buffer, new magwell, new bumper(s) a buffer tube 'extension' as well as some locktite and an allen key.
Here's a comparison of the old magwell next to the new one:
New magwell furthest from the shot, you can see that the feed ramp is a bit beefier, and better sculpted than the original one.
With the magazine and a snap cap installed the difference becomes a little more pronounced:
New magwell on the left, it seats the magazine very nicely. Compared to the original it seats the magazine a bit more tightly, and doesn't allow for over-insertion the same way the original did. Also - I think the pic shows that it's a slightly less drastic ride to the feed ramp from the magazine.
On the buffer tube side of things, the new tube is longer and heavier than the one it shipped with. I guess this explains why the buffer tube extension is needed.
I weighed the new one, it comes in at around 10.5 oz according to this scale:
The old one was ~8.75 on this scale, so the new one has around a couple ounces on the old one.
The buffer tube extension:
Possibly the least elegant part of this kit. It's a piece that threads onto your existing buffer tube, and is meant to be thread locked and set in place with a set screw to your existing buffer tube. I have a UBR that expects to be right next to the receiver acting as the end plate and castle nut, which is not going to work with this fix.
I've got an LMT sopmod stock and conventional buffer tube that I'll switch to - but won't have access to it until next weekend. For now, I've put the UBR tube on, just so I can test the effectiveness of the fixes.
Before shooting:
The UBR is sitting loosely on the tube, just figured it might feel better than planting the tube itself into my shoulder. Inserting the magazine with the bolt forward felt harder than I remembered but it went in well. Racking it was difficult on the way back, but the bolt came forward and chambered around much more smoothly than before the changes.
First three shots:
The first three shots were silky smooth, and the perceived recoil was negligible. The heavier buffer seems to have made things a fair bit smoother!
And that, is all the good times that would be had with the JR yesterday.
Round 4:
The bolt came forward, unseated the round and got stuck. Touching the bolt handle it's clear that it had come loose. When I removed the magazine it came out freely, as did the round.
On inspection it appears the bolt handle was lightly making contact with the rear of the receiver.
There is what looks like a small metal shaving at the rear of the receiver, and the bolt handle is a write-off. I've got a couple spares.
I'm hoping that the failure today was as a result of me not having thoroughly enough 'locktite'd' the bolt hand into place. I don't think the UBR tube is any longer and a conventional carbine tube. I'm not sure if the bolt handle was loose because it wasn't fastened well enough to the bolt, or if it came loose from contact with the rear of the receiver.
I don't have my tools handy, so a further work on this will have to wait until next weekend. My plan is to:
- Disassemble, check out bolt and receiver if ok;
- Replace and locktite the crap out of the bolt handle
- Replace UBR with original buffer tube and stock that shipped with the JR
- Ensure that the bumpers included are sufficient to preclude contact of the bolt handle with the rear of the receiver
- Try, Try again...
What fun would it be if stuff just worked?
