Using a rifle-length tube with a MR556A1 upper

2337 Views 15 Replies 9 Participants Last post by TXHK, Feb 5, 2017

hkbar

Discussion Starter · Jan 23, 2017

I read the old threads on this and couldn't get a clear answer.

I live in a ban state and need to use a fixed stock, most of which use rifle-length tubes. I'd like to use a rifle-length stock anyway for the length of pull.

As we know, the MR556A1 upper comes with its own HK spring and buffer that HK says must be used. Here are solutions I've seen mentioned:

1. Use a rifle-length tube, rifle buffer, and a Wolff XP spring. This is what seems to get recommended a lot in the past threads.
2. Use a rifle-length tube, rifle buffer, and rifle spring.
3. Use a spacer that sits at the end of the tube, behind the spring, to bring the rifle tube length down to carbine length. Spikes sells one.

#3 seems like the best option to me since I can use the HK buffer and spring I already have, but it's also not been talked about much, other than someone saying it's dangerous because the spacer doesn't allow venting (??) .. no idea but that sounded like FUD to me.

Thoughts?

1 - 16 of 16 Posts

dms16

· #2 · Jan 23, 2017

https://www.magpul.com/products/moe-fixed-carbine-stock-mil-spec

or

https://www.magpul.com/products/prs-gen3-precision-adjustable-stock

These will let you keep the OEM buffer tube, spring, and buffer which is best and a quality fixed stock: win/win

or the UBR if it flies with your state. There is the Sully stock as well

hkbar

Discussion Starter · #3 · Jan 23, 2017

dms16 said:
https://www.magpul.com/products/moe-fixed-carbine-stock-mil-spec

The length of pull is too short for me.

https://www.magpul.com/products/prs-gen3-precision-adjustable-stock

It's technically collapsible, so no good for a featureless ban state build, but regardless, the exact question in my OP still applies since it uses a rifle-length tube.

dms16

· #4 · Jan 23, 2017

hkbar said:
The length of pull is too short for me.

An A1 fixed stock has a LOP of 12.875";
The MOE I listed is advertised as 12.4" (and I'm sure you saw this) it will accomodate the .8" PRS thick recoil pad so it can be every bit as long as an A1

If you can't work with an A1 length stock, you must be a monster or you're not doin' some thing right.

hkbar

Discussion Starter · #5 · Jan 23, 2017

dms16 said:
An A1 fixed stock has a LOP of 12.875";
The MOE I listed is advertised as 12.4" (and I'm sure you saw this) it will accomodate the .8" PRS thick recoil pad so it can be every bit as long as an A1

If you can't work with an A1 length stock, you must be a monster or you're not doin' some thing right.

I guess I'm a monster then. With or without a recoil pad, that fixed MOE is going to be shorter than an A2 or a fully-extended M4, at about 13.5". I appreciate the suggestions, but let's keep the thread about using a rifle tube with an MR556A1 upper.

LCSO264

· #6 · Jan 23, 2017

I think his point was that a rifle length tube will likely have a negative impact on reliability. The system was designed and tested around the OEM tube/spring/and buffer combination

wilkster79

· #7 · Jan 23, 2017

OP - can't you find a Magpul stock to fit the MR and just pin it? I used live on a ban state and most gunsmiths can pin almost any stock. The stock HK one is tough but can be done. There's just not much real estate on it to get a pin in there.

Sent from my iPhone using Tapatalk

hkbar

Discussion Starter · #8 · Jan 23, 2017

wilkster79 said:
OP - can't you find a Magpul stock to fit the MR and just pin it? I used live on a ban state and most gunsmiths can pin almost any stock. The stock HK one is tough but can be done. There's just not much real estate on it to get a pin in there.

I thought about it and still might but I'd also like to know what my options are for using a rifle tube since that opens up a lot more possibilities.

baljar

· #9 · Jan 23, 2017

hkbar said:
I guess I'm a monster then. With or without a recoil pad, that fixed MOE is going to be shorter than an A2 or a fully-extended M4, at about 13.5". I appreciate the suggestions, but let's keep the thread about using a rifle tube with an MR556A1 upper.

I am just not sure, I am 6'8 and do not need to extend fully. I would consider your shooting position as the #1 thing I would look at if you came into a course of mine and suggested that an MR223/556 stock does not have enough pull for you.
While this may not directly answer your question, I would be inclined to bet money on a different shooting position solving your problem.

JNAP94

· #10 · Jan 23, 2017

hkbar said:
I thought about it and still might but I'd also like to know what my options are for using a rifle tube since that opens up a lot more possibilities.

The VLTOR A5 system is the longest I know of that works well with the MR556/HK 416 uppers very well. 7 positions and 12.5" LOP IIRC

hkbar

Discussion Starter · #11 · Jan 24, 2017

JNAP94 said:
The VLTOR A5 system is the longest I know of that works well with the MR556/HK 416 uppers very well. 7 positions and 12.5" LOP IIRC

I've heard good things. Unfortunately, I'm looking at fixed stock options because of my state laws.

baljar said:
I am just not sure, I am 6'8 and do not need to extend fully. I would consider your shooting position as the #1 thing I would look at if you came into a course of mine and suggested that an MR223/556 stock does not have enough pull for you.
While this may not directly answer your question, I would be inclined to bet money on a different shooting position solving your problem.

I don't know what the HK stock goes out to, but with a carbine stock, fully extended is about right for me. Another half-inch would be nice.

dms16

· #12 · Jan 24, 2017

hkbar said:
I've heard good things. Unfortunately, I'm looking at fixed stock options because of my state laws.

We know...obviously, you would have to pin that one too

The LOP of an A5 on the 7th position is at least as long as or longer than an A2 stock. With the right stock on an A5, you can get out 14+" LOP. I know this doesn't matter because you insist on a rifle buffer tube.

PS, can someone confirm this guy doesn't have an IP address out of Ballwin, MO :26:

MasterBlaster

· #13 · Jan 24, 2017

hkbar said:
The length of pull is too short for me.

It's technically collapsible, so no good for a featureless ban state build, but regardless, the exact question in my OP still applies since it uses a rifle-length tube.

How do you hold the rifle when you shoot? I generally shoot nose to charging handle and shoot with my stocks fully collapsed or on the second notch.

hkbar

Discussion Starter · #14 · Jan 24, 2017

I don't insist on using a rifle tube, but I was trying to keep this thread about that (before I gave up). Because then future people searching about using a rifle tube won't have to read 9 pages about my body type, LoP preferences, and favorite carbine stocks.

How about we pretend that I asked about using a family heirloom A2 stock instead, as a thought experiment? If the experts' wisdom is that using a rifle tube (with any combination of springs, buffers, and spacers) will make my rifle explode instantly, that's fine too; that's the discussion I was hoping to have.

InshallahTech

· #15 · Feb 5, 2017

Run the A1 rifle system with the wolff spring. It won't hurt a thing and it will cycle just fine.

TXHK

· #16 · Feb 5, 2017

I ran a Magpul MOE rifle stock with a spacer and HK buffer and spring with no issues both suppressed and non-suppressed. If you need a fixed stock solution that's the direction I would go in.

1 - 16 of 16 Posts

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