a few questions...please bare with me

**corey4** · 02-14-18, 17:45

as some of you have seen from some of my more recent threads in this sub forum, i am very new to the AR platform. so please forgive me...

if i have a BCG that has seen some use, and i want a new barrel, should i get a new BCG? if i do the inverse, if i have a barrel with some rounds on it and need a new bolt, should i get a new barrel? if i have both a BCG and a barrel from different rifles that have seen some use, can i mix and match? i would assume functionally it will work, but is there a potential of have a decent combo and then switch the BCG and have the rifle not shoot as good? do they go hand in hand, keep the bolt with the appropriate barrel as the surfaces wear together? if round count matters, what should be the cut off on switching BCG and barrels?

if i were to drop the $$$ for an 18" SPR match barrel, should a new bolt be fitted to the barrel somehow, or is a plain ol' BCG ok?

thanks!

**17K** · 02-14-18, 17:55

You should always check headspace when swapping between bolt and barrel. I like a new bolt with a new barrel, but is absolutely not necessary.

**mack7.62** · 02-14-18, 18:09

I always heard that:
used bolt new barrel - OK
new bolt used barrel - OK
used bolt used barrel - not OK

Course there are always exceptions.

**vicious_cb** · 02-14-18, 18:57

Originally Posted by corey4

as some of you have seen from some of my more recent threads in this sub forum, i am very new to the AR platform. so please forgive me...

if i have a BCG that has seen some use, and i want a new barrel, should i get a new BCG? if i do the inverse, if i have a barrel with some rounds on it and need a new bolt, should i get a new barrel? if i have both a BCG and a barrel from different rifles that have seen some use, can i mix and match? i would assume functionally it will work, but is there a potential of have a decent combo and then switch the BCG and have the rifle not shoot as good? do they go hand in hand, keep the bolt with the appropriate barrel as the surfaces wear together? if round count matters, what should be the cut off on switching BCG and barrels?

if i were to drop the $$$ for an 18" SPR match barrel, should a new bolt be fitted to the barrel somehow, or is a plain ol' BCG ok?

thanks!

Do not mix and match bolts and barrels. Bolts wear with the barrel extension they are mated to. If you swap that bolt with another barrel the chances are that the lugs arent supported evenly like they were with the original barrel increasing your chances of sheering a lug or changing your headspace ect.

**26 Inf** · 02-14-18, 20:31

Originally Posted by corey4

as some of you have seen from some of my more recent threads in this sub forum, i am very new to the AR platform. so please forgive me...

if i have a BCG that has seen some use, and i want a new barrel, should i get a new BCG?

if i were to drop the $$$ for an 18" SPR match barrel, should a new bolt be fitted to the barrel somehow, or is a plain ol' BCG ok?

thanks!

What Vicious CB said. You could just buy a new bolt rather than a complete BCG, but in today's market the complete assembly is not enough higher priced to really save that much money.

A good BCG made of mil-spec materials will run you low-end $75.00 -http://www.monmouthreloading.com/shop/ar15-toolcraft-black-nitride-bcg/ The Toolcraft mil-spec 1B1B6 BCG that everyone was gaga about a while back will run you 85.00 - http://www.wcarmory.com/toolcraft-bc...i-complete.htm

On the other hand, a mil-spec C-158 bolt 'head' will run you that much or more - https://www.bravocompanyusa.com/BCM-...sembly-mp.htm; one of 9310 steel will run you about 50.00 -https://www.dsarms.com/p-15798-dsa-ar15-complete-bolt-head-assembly-mpi.aspx

It doesn't make much sense, unless, of course, you stop to consider that the bolt is the most complete part of the BCG.

A new BCG should be GTG with a new barrel. I use a field gage on rifles I assemble, many don't even do that.

**nightchief** · 02-14-18, 21:08

I've been meaning to buy a head space gauge for a while...

Decent quality gauge?
https://www.brownells.com/gunsmith-t...-prod6646.aspx

**Rogue556** · 02-15-18, 15:38

Originally Posted by nightchief

I've been meaning to buy a head space gauge for a while...

Decent quality gauge?
https://www.brownells.com/gunsmith-t...-prod6646.aspx

I have that gauge and it has worked as intended assembling three different rifles. I could be wrong, but I believe Iraqgunz has recommended that gauge in other threads in the past as well.

**MistWolf** · 02-16-18, 01:08

Originally Posted by corey4

as some of you have seen from some of my more recent threads in this sub forum, i am very new to the AR platform. so please forgive me...

if i have a BCG that has seen some use, and i want a new barrel, should i get a new BCG? if i do the inverse, if i have a barrel with some rounds on it and need a new bolt, should i get a new barrel? if i have both a BCG and a barrel from different rifles that have seen some use, can i mix and match? i would assume functionally it will work, but is there a potential of have a decent combo and then switch the BCG and have the rifle not shoot as good? do they go hand in hand, keep the bolt with the appropriate barrel as the surfaces wear together? if round count matters, what should be the cut off on switching BCG and barrels?

if i were to drop the $$$ for an 18" SPR match barrel, should a new bolt be fitted to the barrel somehow, or is a plain ol' BCG ok?

thanks!

For the most part, you can mix & match safely. However, it's not the ideal situation. If you are going to the trouble to get an SPR barrel, you should also get a dedicated bolt for it. Even better, get the bolt matched to the barrel for best precision.