I am looking to get a spare bolt or BCG for my M&P Sport II but I read that they must be head spaced before use. Is there any place I can simply buy a drop in bolt or complete BCG that will be compatible with my M&P Sport II like PSA etc? Thank you.
Spare Bolt?
- Thread starter enacht
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Jdavis
Member
Most any bolt carrier group will fit your M&P Sport. There is a good YouTube video on the various types available by Mr Guns and Gear. Check it out before you buy.
Arik
Member
All AR 223 direct impingement parts are interchangeable. OK I probably shouldn't say ALL but 99%
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Disabled1
US Veteran
All of the BCG's I have bought from PSA were install and shoot, no problems! 
Personally I do not think you need to keep a spare. Unless you shoot a ton the bolt will most likely outlive you. If you still think you need on get a PSA full auto premium bolt for $69-$89.
Palmetto State Armory 5.56 Premium Full Auto Bolt Carrier Group - 8779
Milspec Carpenter No. 158® steel bolt
Shot Peened Bolt
High pressure tested
Mag particle inspected
Chrome Lined Carrier (AUTO)
Chrome Lined Gas Key
Gas Key Hardened to USGI Specifications
Gas Key Grade 8 Hardened Fasteners
Gas Key Staked Per Mil-Spec
Tool Steel Extractor
Extractor Spring
Extractor O-ring Insert
SKU 8779
By the specs it is a better bolt then what came in the Sport II IMHO.
Palmetto State Armory 5.56 Premium Full Auto Bolt Carrier Group - 8779
Milspec Carpenter No. 158® steel bolt
Shot Peened Bolt
High pressure tested
Mag particle inspected
Chrome Lined Carrier (AUTO)
Chrome Lined Gas Key
Gas Key Hardened to USGI Specifications
Gas Key Grade 8 Hardened Fasteners
Gas Key Staked Per Mil-Spec
Tool Steel Extractor
Extractor Spring
Extractor O-ring Insert
SKU 8779
By the specs it is a better bolt then what came in the Sport II IMHO.
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cyphertext
US Veteran
Checking head spacing is one of those good practices that is rarely done.
Old barrel & new bolt is usually ok
Used bolt & new barrel is usually ok
And I agree with WVSig. Unless you are shooting competitively, the chance of needing to replace the bolt is slim. Many spare bolts end up growing into spare rifles.
Old barrel & new bolt is usually ok
Used bolt & new barrel is usually ok
And I agree with WVSig. Unless you are shooting competitively, the chance of needing to replace the bolt is slim. Many spare bolts end up growing into spare rifles.
Checking head spacing is one of those good practices that is rarely done.
Old barrel & new bolt is usually ok
Used bolt & new barrel is usually ok
And I agree with WVSig. Unless you are shooting competitively, the chance of needing to replace the bolt is slim. Many spare bolts end up growing into spare rifles.
I agree 100% that spare parts like BGC, Stripped lowers or extra uppers always seem to spawn "New Rifles!"
I think the reason people do not check head space is that go-no go gauges cost about $60 and unless you are swapping a lot of bolts it seems like a lot of money. Personally I think the best thing to do is find a good smaller local dealer who you buy stuff from who will check it for you for a small fee.
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Tinhack
Member
The "small fee" at my LGD was about the same price as the gauge. He charged $50 for just about anything. I think that was his minimum charge. Even to tighten a screw. His ammo prices were nearly 40% higher than any other outlet and selection was skimpy. I'm not sure if he just retired or went out business. I'm usually all for supporting the local businesses in my small town but you have to draw the line somewhere.
Any way, the only reason I was looking at this thread is I'm considering a Sport II purchase and wondering why anyone would need/want a spare bolt. Are they not covered by the warranty? Does the bolt have a high failure rate? It bothers me when I hear about folks keeping spare parts for their guns and would certainly affect my decision to buy one.
Any way, the only reason I was looking at this thread is I'm considering a Sport II purchase and wondering why anyone would need/want a spare bolt. Are they not covered by the warranty? Does the bolt have a high failure rate? It bothers me when I hear about folks keeping spare parts for their guns and would certainly affect my decision to buy one.
cyphertext
US Veteran
You must be new to the AR world... many folks keep spare parts for their AR, no matter what the brand. It is a modular rifle that is easy to repair on your own. Others keep parts due to fear of bans and parts becoming hard to get or expensive. Competitors keep parts in the range bag in case of a failure at a competition. And then there are the preppers and the zombie killers...
But yes, S&W will cover your rifle if the bolt breaks, and no, they are not high failure items. But to many, they would rather have the part on hand and fix the rifle themselves vs. shipping it off and waiting two weeks or more for it to be fixed and returned.
vonn
US Veteran
Has anyone ever seen a bolt break? Just curious.
SCAR333
Member
Don't mean to jack this thread, but what exactly is a "full auto" bolt?
29aholic
Member
A FA carrier hasn't had the bottom milled back like a Semi one does. The SA carriers are milled back to the point they wont trip a FA disconnector. Most (not all) AR's I have seen lately have a FA carrier in them.
5point5sixGUY
Member
I have personally seen 2 AR bolts that snapped in half at the cam pin hole. It happened to one of mine and also happened to one of my brothers. The bolt is very thin in that area and I imagine they finally fatigued and snapped.
cyphertext
US Veteran
Bolts will break there, or break the lugs... but it is typically after a high round count. If a bolt were to break early on in use, I would suspect improper heat treatment, or the bolt was built with steel other than what the spec calls for.
Moe Mentum
Member
If your bolt breaks at the range, grab your buddies bolt, and put it in your rifle, they are all interchangeable.
cyphertext
US Veteran
Bad advice... a used barrel with a used bolt should always be checked for headspace. This is the scenario where you are most likely to have a problem.
sgtsandman
US Veteran
I agree with cyphertext. To the most part they are interchangeable but you could be the unlucky one where the tolerances don't stack up right. Better to grab another, complete rifle or call it a day and head home.
That's very interesting.
Do you guys do some hot reloads, or something else that puts more stress on the guns?
Tinhack
Member
Thanks everyone for the explanations. And yes, I am new to ARs. I'd like to get a budget version to replace duty on my Universal M1 Carbine. It has been my day/night shooter for wild dogs, coyotes, hogs and other as needed. (Most recently a rattler.) I had been looking at the S&W and Ruger AR or possibly a Hi-Point 9mm or .45 Carbine. I really like the 9mm Carbine as I already have plenty of ammo. I don't plan to buy until after the holidays or February so I'm gathering all the info I can.
