Is There a Down Side to Sharing the Same BCG For Your 5.56 and 300 Black Uppers?

dreadpirate · Apr 28, 2018

In this scenario, I am sharing the same pre-ban lower between a 5.56 upper and a 300 Black upper. So one could save a few bucks by sharing an existing BCG between the two. Is there any disadvantage doing so in terms of uneven wear or something like that?

3paul10 · Apr 28, 2018

My first thought is as long as the BCG head spaces to both uppers....

danb · Apr 28, 2018

Just dont load 300 blk accidentally in your 556 upper. Bad stuff happens.

dreadpirate · Apr 28, 2018

danb said:
Just dont load 300 blk accidentally in your 556 upper. Bad stuff happens.

Yes, and although everyone boasts about how you can share mags, I would go with mags marked differently to clearly indicate what's in it.

DaemonAssassin · Apr 28, 2018

dreadpirate said:
In this scenario, I am sharing the same pre-ban lower between a 5.56 upper and a 300 Black upper. So one could save a few bucks by sharing an existing BCG between the two. Is there any disadvantage doing so in terms of uneven wear or something like that?

Uneven/accelerated wear on the bolt lugs, due to differences in how the barrel is mounted to the upper (lapped or not), in addition to the same being true with the gas tube/key (alignment issues).

DaemonAssassin · Apr 28, 2018

dreadpirate said:
Yes, and although everyone boasts about how you can share mags, I would go with mags marked differently to clearly indicate what's in it.

I use PMAGS for 556 and Lancer mags for 300BLK.

Squaregrouper · Apr 28, 2018

dreadpirate said:
Yes, and although everyone boasts about how you can share mags, I would go with mags marked differently to clearly indicate what's in it.

DaemonAssassin said:
I use PMAGS for 556 and Lancer mags for 300BLK.

I do plastic for .223/5.56 and aluminum for .300AAC

3paul10 · Apr 28, 2018

These are all good suggestions. I don't have any caliber except 5.56 so I didnt think of this stuff....

omegared24 · Apr 28, 2018

DaemonAssassin said:
Uneven/accelerated wear on the bolt lugs, due to differences in how the barrel is mounted to the upper (lapped or not), in addition to the same being true with the gas tube/key (alignment issues).

This

My quality uppers get a dedicated BCG. My "beater" uppers are using the same BCG.

Alea Jacta Est · Apr 28, 2018

I finally planted some money and harvested a nice crop of bcgs last year. Damn barn loft is full of them now.

You get a bcg. You get a bcg. Everybody gets a BCG!

clandestine · Apr 28, 2018

If you have a properly built upper as DA mentioned, you can swap the entire BCG between New Uppers.

You need to check headspace with each upper you plan to use and you need to check headspace from time to time if you shoot them often as headspace can open up (wear) faster when the bolt is going from upper to upper.

DaemonAssassin · Apr 28, 2018

clandestine said:
If you have a properly built upper as DA mentioned, you can swap the entire BCG between New Uppers.

You need to check headspace with each upper you plan to use and you need to check headspace from time to time if you shoot them often as headspace can open up (wear) faster when the bolt is going from upper to upper.

See, I was actually paying attention in class!

DaemonAssassin · Apr 28, 2018

3paul10 said:
These are all good suggestions. I don't have any caliber except 5.56 so I didnt think of this stuff....

Come to the dark side. We have milk, cookies, and bacon.

ericoak · Apr 28, 2018

I would recommend just matching bolts to barrels for any locked breach gun. They are so cheap, there really isn't a good deal not to.

AlanInSilverSpring · Apr 28, 2018

DaemonAssassin said:
Come to the dark side. We have milk, cookies, and bacon.

That's it ? Nnztg8r (aka Oprah) said we all get bcg's

DaemonAssassin · Apr 28, 2018

AlanInSilverSpring said:
That's it ? Nnztg8r (aka Oprah) said we all get bcg's

I'm still waiting on my BCG. I already have the milk, cookies, and bacon on hand.

DoormanTNT · Apr 28, 2018

Mmmmmmm. Bacon....

Sorry what were we talking about......

Oh yeah, free BCG....yes please I'll take 2.....

Lol..

Alea Jacta Est · Apr 29, 2018

DaemonAssassin said:
I'm still waiting on my BCG. I already have the milk, cookies, and bacon on hand.

Y’all are fully indoctrinated I can see.

You hear “everybody gets BCGs” and ya line up waiting for yours...

I’ve got a book...”Five acres to Freedom”. It’s about how to grow your own and the hard work required.

...or ya can continue to sit and wait.

Livingthedream · Apr 29, 2018

Nnztg8r said:
Y’all are fully indoctrinated I can see.

You hear “everybody gets BCGs” and ya line up waiting for yours...

I’ve got a book...”Five acres to Freedom”. It’s about how to grow your own and the hard work required.

...or ya can continue to sit and wait.

So does this mean we're not getting bcgs?

Alea Jacta Est · Apr 29, 2018

Livingthedream said:
So does this mean we're not getting bcgs?

You sit tight...right there...

Is There a Down Side to Sharing the Same BCG For Your 5.56 and 300 Black Uppers?

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