View Full Version : Question about upper interchangeability
Doc Safari
01-17-11, 09:28
I currently own a BCM carbine length rifle.
If I were to purchase a BCM mid-length upper, are there any interchangeability issues I can expect, or should the upper plug right in and cycle just like the one that came with the rifle?
Do I need to replace the buffer?
Do I need to tweak anything?
The reason I ask is that years ago I owned two identical Colts, and out of curiosity I swapped the complete uppers with each other. The rifles believe it or not suddenly started cycling unreliably until I swapped the uppers back to their original rifle, leaving me to believe there was some little tweak that needed to be made.
Ilove2shoot
01-17-11, 09:36
The reason I ask is that years ago I owned two identical Colts, and out of curiosity I swapped the complete uppers with each other. The rifles believe it or not suddenly started cycling unreliably until I swapped the uppers back to their original rifle, leaving me to believe there was some little tweak that needed to be made.
The AR system is supposed to be plug and play. it is supposed to, and should work just fine. that being said, what happened to you before does sometimes happen. You can not say when it will happen, if it will ever happen again. heck, it can happen on a new build. just takes a little detective work to get it right if it does. if it does happen, there are a few people on this site that can help you figure it out and get it running again.
Since you are changing to different gas system you may also want to test out different buffer weights to find which cycles the best for you. Since the pressures are different between the carbine and middy, a heavier buffer might be needed
Midlength = less pressure = lighter buffer
Since you are changing to different gas system you may also want to test out different buffer weights to find which cycles the best for you. Since the pressures are different between the carbine and middy, a heavier buffer might be needed
Midlength = less pressure = lighter buffer
Yes but you will want to try at least a H buffer in a middy versus the carbine that probably is running in the carbine he has. Its good to try all sorts to find the one that works the best and most reliable
All true as far as function, but you may want to look closely...I don't worry too much about tight or wiggle between upper and lower, but I have noticed with certain charging handle/upper/lower combinations, there is extra wear-rubbing between the bottom rear of the CH and the lower receiver...where you pull the CH back.
Do you have an H buffer now? I'd suspect it will work fine with the middy or carbine gas uppers. Test with you lightest loads to be sure.
Doc Safari
01-20-11, 16:47
Well, I'm debating now.
I was going to order the DD mid-length upper for my DDXV, but now I'm wondering if I'd be better off just selling the complete DDXV rifle and ordering the full mid-length rifle on the theory that I won't have to do any troubleshooting.
I know it would be less expensive to just get the upper, but range time is hard to come by for me lately.
I guess it depends on if you want the full factory warranty on the midlength. No doubt it's the safe way to go but I really don't think it'll be a big deal swapping a middy upper on your lower however you do lose the full rifle warranty. On the other hand you don't have another firearm in your name if you swap uppers.
Guess you have to run the numbers to see the cost of both options.
Also if your present lower says Savannah, GA the new one probably will say Black Creek, GA. Of course they're not far apart but I love the name Savannah. :D
BTW, I just got my Daniel Defense 16" midlength and it dropped on my S&W lower nicely. Didn't get to fire it today but everything looks good and works smoothly.
Doc, I see no reason for you to follow that course, of selling this to get that. Any increased value would be countered by the cost of sales...unless someone wants to give you more than it's worth (could happen). Warranties should exist for problems regardless.
Doc Safari
01-21-11, 11:10
I tend to like the idea of simply ordering the middy upper because it's less money than a whole new rifle, and it would give me a spare carbine upper. I also believe that probably it would be plug and play on the lower with no cycling issues but there's always the possibility I'd have to change buffers or something. That would take burning up expensive ammo to find out, and I like the idea of buying a complete rifle that someone else has already test fired.
I never really liked the way the DD is set up with the receiver mounted port for the single point sling and no front swivel, either. One reason I prefer my BCM is that the sling swivels are old school like me. I'd have to install a front swivel or live with the way the DD is set up in order to keep it.
Right now I'm in contact with BCM to check availability of their Mid 16 Model 0, so we'll see what happens.
Doc, for your sling it's better to run a BFG UWL anyhow, IMHO. Also, I'd bet you won't have any issues with buffers from carbine to mid, either. I use a car buffer, and have friends who use H1 and H2. None of us has had any problems. Also, it's pretty unlikely the factory test fires using a wide range of ammo, like it sounds you want to. I think your original post and history with the Colt upper swap problem was not normal. I've used rifle lowers, collapsible, car, h1 with car, mid, rifle uppers. Mix and match, plug and play, no problems. Even if you do your complete rifle thing, it's "possible" you could end up with a canted FSB or gas port not lined up, or whatever. IMHO again, if you stick with good name manufacturers like BCM or DD, they will take care of you, so just go for it!
Doc Safari
01-21-11, 11:52
Doc, for your sling it's better to run a BFG UWL anyhow, IMHO. Also, I'd bet you won't have any issues with buffers from carbine to mid, either. I use a car buffer, and have friends who use H1 and H2. None of us has had any problems. Also, it's pretty unlikely the factory test fires using a wide range of ammo, like it sounds you want to. I think your original post and history with the Colt upper swap problem was not normal. I've used rifle lowers, collapsible, car, h1 with car, mid, rifle uppers. Mix and match, plug and play, no problems. Even if you do your complete rifle thing, it's "possible" you could end up with a canted FSB or gas port not lined up, or whatever. IMHO again, if you stick with good name manufacturers like BCM or DD, they will take care of you, so just go for it!
I agree with most of your post. My experience with Colt was during one of those seemingly many periods when people criticized their quality control.
I've contacted Daniel Defense to see if I'll void the warranty if I put one of their uppers on one of their rifles.
That alternative sure would be easier and I'd have a spare carbine upper. Maybe I'd just have the front swivel installed and be done with it. :cool:
...I've contacted Daniel Defense to see if I'll void the warranty if I put one of their uppers on one of their rifles.
That alternative sure would be easier and I'd have a spare carbine upper. Maybe I'd just have the front swivel installed and be done with it. :cool:
Sounds like the smart way to go. I can't see how this would affect the warranty on the original rifle, just keep the carbine upper as you already said.
And you'd only have to spend about $300 more to end up with two ARs. :D
Doc Safari
01-27-11, 15:48
Just in case you guys are curious, here is Daniel Defense's response to my email asking if I should change the buffer or spring when putting the middy upper on the carbine lower, and if it would void the warranty:
"Thank you for your interest in Daniel Defense and our products. You can assemble the upper onto your current lower with no issues and without needing any additional components. It does not affect your warranty in any way."
Refreshing to deal with a manufacturer that knows their stuff and doesn't feed you BS. Thumbs up for Daniel Defense.
Thanks for sharing the email, Doc G.
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.