Robinson Arms XCR: GO TO WAR GUN??

[astroman]

I forgot that the Russians and Chinese employed Elves at low wages to break in the guns to reduce cost before sending the out. I guess same goes Colt AR's, never heard of those needing break in either. How can Colt keep cost down? I thought employing Elves for low wages were illegal in this country?

Cute. The problem, though, is simple: when new, the system needs extra force in the gas system to cycle reliably. When "broken in", it requires less force, and therefore less gas.

The need for more force can only arise from 2 things: 1) the spring needs broken in, and/or 2) the action tolerances need worn in a bit.

So it would be interesting to know, and to know if RobArms knows, what/where the source for the need of the break-in period comes from.

My impression is that it has been in the spring, given that I can feel it requires less force to cycle by hand than when I first bought it. If the action really was that tight, it would bind up a lot. But the action has never actually binded up, and the wear on the moving parts isn't all that bad.

So I think it comes in from the spring mainly, with a potential secondary influence from the action.

Think of the springs in your mags. Pistol mag springs are certainly quite stiff when new...but the more they're used/cycled, the easier it becomes to push bullets down into them.

RobArms could have, then, easily just sold the gun with a single, nonadjustable gas setting, setting 4. That cycles everything, even when brand new out of the box, without break-in. Or made a setting even larger than #4, for even more out of the box assurance. For some reason that wasn't a good idea. Too hard on the recoil pad from what people say who've left it on #4 the whole time. Could use a better recoil pad then...

I'm not sure what the philosophy/reason is behind allowing the user to reduce the gas setting after the spring gets worn down a bit. Yes it does allow the user to reduce recoil, allows the user to be more accurate, etc., but for all the confusion it gives people who aren't rocket scientists, maybe they didn't need to bother. Also not sure why the XCR requires this kind of finesse when an AK47 does not...

[EricCartmann]

I forgot that the Russians and Chinese employed Elves at low wages to break in the guns to reduce cost before sending the out. I guess same goes Colt AR's, never heard of those needing break in either. How can Colt keep cost down? I thought employing Elves for low wages were illegal in this country?

Cute. The problem, though, is simple: when new, the system needs extra force in the gas system to cycle reliably. When "broken in", it requires less force, and therefore less gas.

The need for more force can only arise from 2 things: 1) the spring needs broken in, and/or 2) the action tolerances need worn in a bit.

So it would be interesting to know, and to know if RobArms knows, what/where the source for the need of the break-in period comes from.

My impression is that it has been in the spring, given that I can feel it requires less force to cycle by hand than when I first bought it. If the action really was that tight, it would bind up a lot. But the action has never actually binded up, and the wear on the moving parts isn't all that bad.

So I think it comes in from the spring mainly, with a potential secondary influence from the action.

Think of the springs in your mags. Pistol mag springs are certainly quite stiff when new...but the more they're used/cycled, the easier it becomes to push bullets down into them.

RobArms could have, then, easily just sold the gun with a single, nonadjustable gas setting, setting 4. That cycles everything, even when brand new out of the box, without break-in. Or made a setting even larger than #4, for even more out of the box assurance. For some reason that wasn't a good idea. Too hard on the recoil pad from what people say who've left it on #4 the whole time. Could use a better recoil pad then...

I'm not sure what the philosophy/reason is behind allowing the user to reduce the gas setting after the spring gets worn down a bit. Yes it does allow the user to reduce recoil, allows the user to be more accurate, etc., but for all the confusion it gives people who aren't rocket scientists, maybe they didn't need to bother. Also not sure why the XCR requires this kind of finesse when an AK47 does not...

You sure it's the spring? You do know that springs are stronger when new don't you? You sure it's just not the parts being tight and just need time to wear in? That is why lube and gas at the highest setting is also recommended during break in. To help with the cycling.

Or do you need weaker springs to make it work better? Please Discuss.

[astroman]

For the reasons I state above regarding this curious need for break-in, plus the issue of the frequent bolts coming loose, I would not think this a good "war" rifle. With another million or two for R&D, it would be a great "war" gun. The concepts are great, regarding the action controls, etc. I am sure it could be made to work as reliably as anything else out there. But they didn't get the DoD contract and so they never got to go to the next level of development.

As a plinking gun it's great fun. Or for pretty much ANY other civilian purpose, where you have the time to spend maintaining it. For shtf...no, not at all. Not until you could be reasonably sure that your neighbor might have a spare part or two for it. That would require a rate of sale that nothing has ever experienced. It's taken the AR platform, what, 40-50 years to get to that point. You better have an AR in your closet for shtf.

[EricCartmann]

For the reasons I state above regarding this curious need for break-in, plus the issue of the frequent bolts coming loose, I would not think this a good "war" rifle. With another million or two for R&D, it would be a great "war" gun. The concepts are great, regarding the action controls, etc. I am sure it could be made to work as reliably as anything else out there. But they didn't get the DoD contract and so they never got to go to the next level of development.

As a plinking gun it's great fun. Or for pretty much ANY other civilian purpose, where you have the time to spend maintaining it. For shtf...no, not at all. Not until you could be reasonably sure that your neighbor might have a spare part or two for it. That would require a rate of sale that nothing has ever experienced. It's taken the AR platform, what, 40-50 years to get to that point. You better have an AR in your closet for shtf.

What happened to "cute, when new the system blah blah blah"???

[astroman]

You sure it's the spring? You do know that springs are stronger when new don't you? You sure it's just not the parts being tight and just need time to wear in? That is why lube and gas at the highest setting is also recommended during break in. To help with the cycling.

Or do you need weaker springs to make it work better? Please Discuss.

Yes that's what I was saying. When new the spring is stronger, therefore requiring more force in the gas system to cycle reliably. After 3 or 4 hundred cycles, just like with your pistol mag springs, the spring has weakened, and so the action cycles more easily, therefore requiring less gas.

I have not found that the action was all that tight...there was never any indication that it was binding nor have I ever heard of that for the XCR. There is SOME wear on the moving parts, but it's not that significant. As I said, I can FEEL (by memory) the difference in the arm strength it took to cycle the action by hand now, as compared to when it was new. So I think that most of the break-in comes from the spring getting weakened a bit from cycling.

I'm not sure why RobArms didn't just use a weaker spring from the get-go, then. However, I am sure there would be a very fine area, allowing for balance between variations in factory ammo loads etc., and spring strength.

However, given that basically EVERYONE can use gas setting #1, or even S, after the break-in period, it does seem as though they went overkill on the spring and could have went with a weaker one out of the factory. Presumably this would have went a long way to obviating the break in period. If they didn't experiment with this and have an answer for it, I would be very disappointed.

[astroman]

Obviously, you can't go TOO weak of a spring, or else it won't cycle fast enough or with enough force. But the XCR certainly cycles just fine with a spring strength at whatever spring-constant it gets down to after a few hundred cycles, with pretty much any ammo I've ever heard people talking about. Once that spring is weakened the system runs fine.

It would be interesting to know by what percentage the spring strength has reduced after a few hundred cycles, and what its spring-constant value is. I wonder what would happen if they started with a spring at that strength....would a spring like that get too soft after a few hundred rounds? It would cycle just fine out of the box, then, but perhaps after the spring is broken in it would have been too weak. Maybe they needed to start with a strong spring which asymptotes down to the value it is after breaking in...maybe springs are just that crappy, or better ones are too expensive...

[DJ]

This is just too easy to resolve, simply purchase a new spring and install it as a temporary replacement on a well broken-in XCR. Voila, the spring question is answered. They're quite inexpensive as I learned when inquiring about same. (Mine is sort of many wiggles S-shaped over its length as installed over its guide rod and thus undesirably rubs against its housing tube with the potential of someday(long in the future) wearing through, lube notwithstanding -so I inquired about acquiring another to place in my spare parts bin).

[astroman]

This is just too easy to resolve, simply purchase a new spring and install it as a temporary replacement on a well broken-in XCR. Voila, the spring question is answered. They're quite inexpensive as I learned when inquiring about same. (Mine is sort of many wiggles S-shaped over its length as installed over its guide rod and thus undesirably rubs against its housing tube with the potential of someday(long in the future) wearing through, lube notwithstanding -so I inquired about acquiring another to place in my spare parts bin).

Now someone's thinking. Take an XCR that will run on 1 or S, install a brand new factory-spec spring, run the same ammo on 1 or S still, and see if it screws up and needs more gas. Also put a weigh-scale on the charging handle (fish scale would work) before and after and see what the difference in maximum force is required to manually cycle.

Then someone could even get a custom, brand new, weaker spring and see how it cycles on the lowest gas, etc etc. ...wait, that's R&D RobArms should all have already done well before the XCR was ever sold.

[EricCartmann]

Yes that's what I was saying. When new the spring is stronger, therefore requiring more force in the gas system to cycle reliably. After 3 or 4 hundred cycles, just like with your pistol mag springs, the spring has weakened, and so the action cycles more easily, therefore requiring less gas.

I have not found that the action was all that tight...there was never any indication that it was binding nor have I ever heard of that for the XCR. There is SOME wear on the moving parts, but it's not that significant. As I said, I can FEEL (by memory) the difference in the arm strength it took to cycle the action by hand now, as compared to when it was new. So I think that most of the break-in comes from the spring getting weakened a bit from cycling.

I'm not sure why RobArms didn't just use a weaker spring from the get-go, then. However, I am sure there would be a very fine area, allowing for balance between variations in factory ammo loads etc., and spring strength.

However, given that basically EVERYONE can use gas setting #1, or even S, after the break-in period, it does seem as though they went overkill on the spring and could have went with a weaker one out of the factory. Presumably this would have went a long way to obviating the break in period. If they didn't experiment with this and have an answer for it, I would be very disappointed.

never heard of mag springs needing to be broken in, I have seen worn mag springs though.

[astroman]

never heard of mag springs needing to be broken in, I have seen worn mag springs though.

Dude, never said mag springs need to be broken in. I said they get weaker with time, after cycling...as a function of the number of cycles, actually.

Therefore, since the XCR works better after the spring has been broken in, they could try just starting with a weaker spring in the first place. It may very well be that a weaker spring doesn't degrade as fast as a heavy spring, as a function of cycling. It may be that there are better spring materials (better metals/alloys) to use that don't weaken as fast, given a weaker spring to start with.
This should all be in RobArms R&D notebooks somewhere.