Hello all I just joined the forum. I recently traded for a bushmaster ar10 orc. I love this gun it is pretty accurate. I want to make it even more accurate, new barrel, put a quad rail on it, trigger and gas block. Just trying to feel out what I should go with and what opinions are on the subject. I have built quite a few ar15's and this will be my first ar10, I have heard good things about the rifles except for over gassing. I want to make this an accurate shooter, I have many blot actions that I shoot at over 600 yards often, so that is what I am looking for in my ar10. Thanks in advance for any advice or tips.
Need to upgrade my new bushmaster 308 orc
- Thread starter iwrfla
- Start date
If you're so disenchanted, I would sell it a get an AR you like without having to do all those mods. No guarantee you'll like any better after all your time and effort spent. Your choice and dime though...
PS: A hundred rounds is a tad. Now 1000-1500 rounds is a bunch!
PS: A hundred rounds is a tad. Now 1000-1500 rounds is a bunch!
Last edited:
What do you have in the rifle now? How much will the accessories you want to add cost? Don't forget to include shipping and tax. He much is your time worth? It is likely you can come out ahead by buying a complete rifle that is set up how you want it. And, cobbled together rifles generally are harder to sell than a rifle that came from a reputable manufacturer as a complete package (piece of mind if you get into something that you might not like).
First and foremost, your rifle is NOT an AR-10. When you go looking for options/accessories/parts/etc., if you find something that is built for an "AR-10" it likely will NOT work with your BM. Armalite = AR-10 even though many use it loosely as a term to refer to ALL .308 ARs out there. Not a big deal until you go to buy a platform-specific part (like a handguard/barrel nut for example) and you get the WRONG one.
The BM is essentially a DPMS LR-308 "pattern" rifle, so when sourcing parts, that's the platform you should be looking for in lieu of "AR-10."
All of that said...what do you want to have when you are done with this "project?"
I ask that very important question because your goals should dictate the direction you go with any "upgrades" or "enhancements" to the rifle. To jump on the same line of thought as others in this thread...how much you "dump" into this rifle may dictate that selling it and buying something else is the more prudent and cost-effective course of action. i.e. - once you have yanked the handguard, barrel, gas system and trigger out...you more or less have an overpriced receiver set that you are rebuilding somewhat from the ground up. To that end, it may be better to scrap the ORC in its entirety and start over with a different complete rifle (or receiver set if you want to go for a full build).
In any event...knowing where the rifle stands now (in terms of its performance at least) and where you ultimately want it to be would be helpful in getting you pointed in the right direction.
The BM is essentially a DPMS LR-308 "pattern" rifle, so when sourcing parts, that's the platform you should be looking for in lieu of "AR-10."
All of that said...what do you want to have when you are done with this "project?"
I ask that very important question because your goals should dictate the direction you go with any "upgrades" or "enhancements" to the rifle. To jump on the same line of thought as others in this thread...how much you "dump" into this rifle may dictate that selling it and buying something else is the more prudent and cost-effective course of action. i.e. - once you have yanked the handguard, barrel, gas system and trigger out...you more or less have an overpriced receiver set that you are rebuilding somewhat from the ground up. To that end, it may be better to scrap the ORC in its entirety and start over with a different complete rifle (or receiver set if you want to go for a full build).
In any event...knowing where the rifle stands now (in terms of its performance at least) and where you ultimately want it to be would be helpful in getting you pointed in the right direction.
I've not used a Bushmaster or assembled one but my Mega MaTen uses the same dimension of pins for the trigger and hammer pins as an AR15. So if you wanted to buy a better trigger then it should be just a matter of pushing the old pins out removing the old parts and putting in the new. The added benefit of this is if you do choose to buy a different rifle then you can just put your nicer trigger in the new gun also.
According to this thread
Bushmaster .308 ORC and barrel change? - AR15.COM
Your barrel nut is the DPMS thread pattern so if you wanted to swap the handguards for a rail that is what you'll want to shop for. I have a Troy TRX extreme on my MaTen and like it.
I'd suggest this one
Rainier Arms™ | Browse | Railed Forearms | Troy BattleRail TRX-308 - 13.8
Take note that there are 2 heights for the DPMS thread pattern and a PDF to the difference is on Rainiers link above. Personally I don't see the point in a quad rail anymore. I have had them, and just for me, there ends up being a lot of empty rail space. And you have to consider the added amount of metal that is needed to make a quad rail vs the slimmer round rails = more weight savings. 308s are a good bit heavier than ar15s so for me its a question of "why make it heavier than it needs to be?"
Bushmaster .308 ORC and barrel change? - AR15.COM
Your barrel nut is the DPMS thread pattern so if you wanted to swap the handguards for a rail that is what you'll want to shop for. I have a Troy TRX extreme on my MaTen and like it.
I'd suggest this one
Rainier Arms™ | Browse | Railed Forearms | Troy BattleRail TRX-308 - 13.8
Take note that there are 2 heights for the DPMS thread pattern and a PDF to the difference is on Rainiers link above. Personally I don't see the point in a quad rail anymore. I have had them, and just for me, there ends up being a lot of empty rail space. And you have to consider the added amount of metal that is needed to make a quad rail vs the slimmer round rails = more weight savings. 308s are a good bit heavier than ar15s so for me its a question of "why make it heavier than it needs to be?"
Thanks for all the advice people. I really like the rifle, shoots well. I don't have any cash invested in the rifle, I got it in a trade for a great deal. I want this to be my long range rifle (over 500 yards) along with my 7mm. I've heard different things about barrel length, I also heard that it doesn't make much difference but with the trigger, adjustable gas block and free float rail it makes a huge difference in accuracy. My gas block is just a gas block no sights.
Ok...since you are set on building out your BM, here's what I'd suggest:
1) Barrel - There are many "off-the-shelf" barrels that are of excellent quality for the DPMS pattern rifles, including the following (I'd personally get at least an 18" barrel for beyond 600yds on a regular basis and if you want to go to 1k, then 20" and longer is never a bad thing as you'll get a fair bit more MV with the longer barrels, but in turn, you'll add more weight, length, bulk to the rifle...your call):
Rainier Arms™ | Browse | 7.62MM / .308 WIN | Rainier Arms UltraMatch™ .308 Barrel - 18
Rainier Arms™ | Browse | 7.62MM / .308 WIN | Rainier Arms UltraMatch™ .308 Barrel - 20
Rainier Arms™ | Browse | 7.62MM / .308 WIN | Rainier Arms UltraMatch™ .308 Barrel - 24
Lilja Precision Rifle Barrels
JP - Barrels (They have both their 20" and 22" med contour barrels in stock now, and they include a matching, headspaced .308 Enhanced bolt)
2) Trigger - Geissele is where it is at for all things AR-trigger. They have a huge selection of different trigger options which will all work on the DPMS/KAC pattern rifles. My personal preferences are for the non-adjustable models (less to go wrong) including the SSA-E and SD-E for a lighter weight, match-style trigger and the basic SSA for a slightly heavier trigger. See here for more info: Geissele Automatics - Quality Triggers for the Warfighter and Competitor If you prefer a single-stage trigger...the Timney drop-in units are good in my experience with a variety of models over the years, as is the AR Gold trigger from ATC.
3) Gas Block - The options available to you will depend on the barrel that you select (what size journal the barrel has), what specific features you want in a block (i.e. - do you want a positional block such as a 3-position for "On", "Suppressed" and "Off" or a more user-adjustable block?), and whether you select a handguard that the block will have to fit under or not. The best I have used for a positional block are those from Paladin Machine. The best user-adjustable type blocks are those from SLR Rifleworks (DA7 Gen 2, detent adjustable with roughly 16 different settings from off to full open), Syrac Ordnance (also detent adjustable) and Seekins (set screw with a brass locking screw to hold the adjustment setting once set until you loosen the brass screw and adjust).
4) Handguard/Rail - Again...there are more options that you can count. Best for you depends entirely on what features you want/need aside from "free-floating" (which almost all are these days). Here is a link to Rainier Arms' .308 AR handguard page and one from MidwayUSA to give you an idea of some of the more popular options out there, but even those pages don't hit all the options available...if you can describe more of what you want/need, we can probably get you into the ballpark a lot quicker:
Rainier Arms™ | Browse | Railed Forearms
Handguards | AR-10 LR-308 | Gun Parts by Gun Make & Model
Good luck!
Thoroughly clean the barrels bore and chamber.....Then,
I would free float the barrel first. Your barrel might be a better shooter, might not... you won't know until it is free floated.
Personally I don't like the Quad Rail Cheese grater hand guards... (no offense, and to each his own )
But make sure whatever your hand guard choice has a decent amount of ID room for an Adj. GB.... any contact between the gas block and handguard negates consistent accuracy. So allow for barrel whip room as well.
Then Try a box or 2 of 168gr FGMM out of it... IMHO, that ammo is pretty much a standard for .308 ammo.
Do not assume your first 5rd groups to be indicative of the accuracy potential of your barrel... I believe ammo needs to "season the bore" ( 5-10rds ) prior to shooting for groups.
I have slowly seen groups tighten up when changing one brand/type ammo to the next.
Not every time, but enough to believe in seasoning a bore to the next test ammo.
Then a better trigger... you can shoot good groups with a USGI spec type trigger, it just requires typically much more concentration.
Then if you want a better barrel, consider spending 350+ ish on a well respected barrel manufacturer's product.
And by this I mean, Ballistic Advantage and Faxon make good barrels... but a additional 100bucks will go a LONG way towards "increasing your odds" that your barrel shots well.... I have great respect for Criterion barrels.
IMHO , that extra spent now money is a bargain in the real world... you might spend that much just trying to make a lesser barrel shoot to your expectations.
If it is "over-gassed" , an Adj. GB will help quite a bit in taming the perceived recoil impulse.
Buy a quality click adjustable GB. ...those set screw ones, will work.. but ( IMHO ) are fussy to tune/ set.
If your barrel has a .750 gas journal size... make sure the replacement barrels gas journal is the same size to save a few bucks down the road if you decide to upgrade your barrel.
308's in this price range typical benefit from a Adj. GB, especially in the perceived recoil, and feeding wise.... easier on you , easier on the fired brass, easier on the parts, easier follow up shots.
If you decide to change the stock to a different carbine one... Limbsaver makes a couple of excellent recoil pads for various Magpul carbine stocks.... FAR, FAR softer then the OEM Magpul ones.
Bottom of the link... 3 different ones. And have proven to be plenty durable.
https://www.nokick.com/AR_15_Stocks_s/127.htm
Please keep us updated as to your progress !
I would free float the barrel first. Your barrel might be a better shooter, might not... you won't know until it is free floated.
Personally I don't like the Quad Rail Cheese grater hand guards... (no offense, and to each his own )
But make sure whatever your hand guard choice has a decent amount of ID room for an Adj. GB.... any contact between the gas block and handguard negates consistent accuracy. So allow for barrel whip room as well.
Then Try a box or 2 of 168gr FGMM out of it... IMHO, that ammo is pretty much a standard for .308 ammo.
Do not assume your first 5rd groups to be indicative of the accuracy potential of your barrel... I believe ammo needs to "season the bore" ( 5-10rds ) prior to shooting for groups.
I have slowly seen groups tighten up when changing one brand/type ammo to the next.
Not every time, but enough to believe in seasoning a bore to the next test ammo.
Then a better trigger... you can shoot good groups with a USGI spec type trigger, it just requires typically much more concentration.
Then if you want a better barrel, consider spending 350+ ish on a well respected barrel manufacturer's product.
And by this I mean, Ballistic Advantage and Faxon make good barrels... but a additional 100bucks will go a LONG way towards "increasing your odds" that your barrel shots well.... I have great respect for Criterion barrels.
IMHO , that extra spent now money is a bargain in the real world... you might spend that much just trying to make a lesser barrel shoot to your expectations.
If it is "over-gassed" , an Adj. GB will help quite a bit in taming the perceived recoil impulse.
Buy a quality click adjustable GB. ...those set screw ones, will work.. but ( IMHO ) are fussy to tune/ set.
If your barrel has a .750 gas journal size... make sure the replacement barrels gas journal is the same size to save a few bucks down the road if you decide to upgrade your barrel.
308's in this price range typical benefit from a Adj. GB, especially in the perceived recoil, and feeding wise.... easier on you , easier on the fired brass, easier on the parts, easier follow up shots.
If you decide to change the stock to a different carbine one... Limbsaver makes a couple of excellent recoil pads for various Magpul carbine stocks.... FAR, FAR softer then the OEM Magpul ones.
Bottom of the link... 3 different ones. And have proven to be plenty durable.
https://www.nokick.com/AR_15_Stocks_s/127.htm
Please keep us updated as to your progress !
