New SR25/M110 Barrels Vs. Issue M110 Barrels?

Strykervet

Strykervet

ain'T goT no how whaTchamacalliT
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    • Jun 5, 2011
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    #1
    So I'd like a new barrel, a spare to put away for my SR25. The new SR25's and M110's are identical except for suppressor mount and stock (SR has a better stock, M110 has a better mount, why they aren't the same is anyone's guess). I have the 20" APR and it uses the QDC mount and suppressor. My question is will the military issue M110 barrel that uses the reflex suppressor work as a replacement barrel? Questions coming up are:

    Barrel extension dimensions. Are they the same, different, if so how? What about the bolt?

    Gas block. The new one is under the URX4 rail and is indexed by a notch on the barrel and is retained by a castle nut that threads on the front. All of this is concealed under the tube so there are no pins or set screws (which KAC doesn't use anyway). Is the M110 that uses the reflex can made the same way? Does the gas block have a threaded portion and is the gas block indexed TDC?

    Muzzle. KAC uses 3/4-24 threads but there are two different kinds. I'm assuming KAC threads 'em the same 3/4 but just checking.

    In short, would a stripped M110 barrel work as a replacement for a new URX4 SR25, or will I be forced to buy a new gas block and shorter URX4 or URX2 assy.? Plan on using the QDC can regardless.

    Or would it be advantageous to just have one custom cut to my specs later? I haven't had good luck getting custom barrels done though, Satern had me wait years just to totally fall through. Obermeyer is making these barrels and I'd like one but not if it wont' fit. Suggestions? I want the absolute best cut rifle barrel made by a pro (while they're still in business and alive). A fellow on the 'Hide is working with Obermeyer to make a bunch of M110 and Mk11 barrels; I know the Mk11 won't work but what about the M110? I'd really like one if possible.

    I have a contact at KAC but haven't been able to reach him yet. Hoping someone here knows the difference between the new and older ones.
     
    #2
    I'm not as knowledgeable with KAC SR25 products as I would like to be, but I'm fairly certain that the upper receivers are not proprietorial, and so a DPMS extension or Armalite pattern will work. So fitting one with a custom Cut Barrell would not be a problem. I have been flirting with the idea of taking a new SR25 and installing a Bartlein barrel with a match 6.5 CM Chamber. I've since put that idea on the backburner due to the release of the new Draco's barrel with a lifetime guarantee. And SR25 with a 22" 6.5Creedmoor draco's barrel would be a wicked combination.
     
    #3
    Strykervet said:
    So I'd like a new barrel, a spare to put away for my SR25. The new SR25's and M110's are identical except for suppressor mount and stock (SR has a better stock, M110 has a better mount, why they aren't the same is anyone's guess). I have the 20" APR and it uses the QDC mount and suppressor. My question is will the military issue M110 barrel that uses the reflex suppressor work as a replacement barrel? Questions coming up are:

    Barrel extension dimensions. Are they the same, different, if so how? What about the bolt?

    Gas block. The new one is under the URX4 rail and is indexed by a notch on the barrel and is retained by a castle nut that threads on the front. All of this is concealed under the tube so there are no pins or set screws (which KAC doesn't use anyway). Is the M110 that uses the reflex can made the same way? Does the gas block have a threaded portion and is the gas block indexed TDC?

    Muzzle. KAC uses 3/4-24 threads but there are two different kinds. I'm assuming KAC threads 'em the same 3/4 but just checking.

    In short, would a stripped M110 barrel work as a replacement for a new URX4 SR25, or will I be forced to buy a new gas block and shorter URX4 or URX2 assy.? Plan on using the QDC can regardless.

    Or would it be advantageous to just have one custom cut to my specs later? I haven't had good luck getting custom barrels done though, Satern had me wait years just to totally fall through. Obermeyer is making these barrels and I'd like one but not if it wont' fit. Suggestions? I want the absolute best cut rifle barrel made by a pro (while they're still in business and alive). A fellow on the 'Hide is working with Obermeyer to make a bunch of M110 and Mk11 barrels; I know the Mk11 won't work but what about the M110? I'd really like one if possible.

    I have a contact at KAC but haven't been able to reach him yet. Hoping someone here knows the difference between the new and older ones.
    Click to expand...

    You say you have a contact at KAC..just curious sir, do you know if KAC is making their barrels in-house? Ie on their site most of their rifles are listed with cut-rifled chrome lined barrels? Do they have their own rifling machine or are they buying Obermeyers/Kriegers/etc whatever brand and having them chrome lined? I may have asked you this before if so I apologize, as my name implies my memory aint the best.. hah :p
     
    #8
    Forgetful Coyote said:
    So basically the current/recent SR25 cut rifled chrome lined 5R barrels were a mish-mash of Obermeyer blanks that were then chrome lined + KAC fully in-house cut rifled chrome lined barrels??
    Click to expand...

    No. KAC stopped using Obermeyer barrels around 2008. Knights now makes their own barrels. The M110 barrels were Chrome-Moly and not chrome-lined.

    Mike_Honcho said:
    If a person has an ER - where can I read up on the differences between barrel profiles for either? Is the gas block on the ER the same?

    TIA
    Click to expand...

    The SR25 ER barrel is very similar to the Mk11. I am not an ER expert, but will your ER accept an Mk11 suppressor? I believe the gas block on the ER is the M110 gas block. If memory serves me correctly, the ER has a hodge-podge of Mk11 and M110 parts, so if you were going the clone route, you would need to choose Mk11 or M110. I think a rail swap gets you pretty close to a Mk11, as you have what was the M110 rail. If you wanted to replace the gas block, you could, but the later years' Mk11s had the M110 gas block, so you would be good to go.

    Forgetful Coyote said:
    So basically the current/recent SR25 cut rifled chrome lined 5R barrels were a mish-mash of Obermeyer blanks that were then chrome lined + KAC fully in-house cut rifled chrome lined barrels??
    Click to expand...

    Yes, or you can get a new matching bolt. The logistics of the former might be tough, it would mean you would need to send your bolt pretty far in advance of getting the barrel, since there are two more steps after chambering: finishing / coating and then gas block installation.

    For anyone interested in the process, the opportunity, or editorializing about Mr. Obermeyer, here is a quick read: https://charliescustomclones.com/blogs/news/precision-barrel-making-the-mk11-and-m110
     
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    #9
    longshot2000 said:
    No. KAC stopped using Obermeyer barrels around 2008. Knights now makes their own barrels. The M110 barrels were Chrome-Moly and not chrome-lined.



    The SR25 ER barrel is very similar to the Mk11. I am not an ER expert, but will your ER accept an Mk11 suppressor? I believe the gas block on the ER is the M110 gas block. If memory serves me correctly, the ER has a hodge-podge of Mk11 and M110 parts, so if you were going the clone route, you would need to choose Mk11 or M110. I think a rail swap gets you pretty close to a Mk11, as you have what was the M110 rail. If you wanted to replace the gas block, you could, but the later years' Mk11s had the M110 gas block, so you would be good to go.



    Yes, or you can get a new matching bolt. The logistics of the former might be tough, it would mean you would need to send your bolt pretty far in advance of getting the barrel, since there are two more steps after chambering: finishing / coating and then gas block installation.

    For anyone interested in the process, the opportunity, or editorializing about Mr. Obermeyer, here is a quick read: https://charliescustomclones.com/blogs/news/precision-barrel-making-the-mk11-and-m110
    Click to expand...
    I was referring to the various civvie SR25 models which had under the online description "cut rifled 5R chrome lined". These are KAC produced barrels? As in they have their own rifling machines and all?
    If that's the case, why do they still use outsourced CHF barrels on some of the SR15's? Is it cheaper to just buy some CHF FN 5.56 barrels and use those vs tooling up/cut rifling + chrome lining the SR15 barrels like they do the SR25 chrome lined models?
     
    #10
    Forgetful Coyote said:
    I was referring to the various civvie SR25 models which had under the online description "cut rifled 5R chrome lined". These are KAC produced barrels? As in they have their own rifling machines and all?
    If that's the case, why do they still use outsourced CHF barrels on some of the SR15's? Is it cheaper to just buy some CHF FN 5.56 barrels and use those vs tooling up/cut rifling + chrome lining the SR15 barrels like they do the SR25 chrome lined models?
    Click to expand...
    For one CHF is often the requirement posed for the 5.56 SR15/16 lines. But that's not to say in house cut rifled chrome lined 556 won't happen...
     
    #11
    J.R. makes the cut-rifled barrels at Knight's. I can't remember if he started in Wisconsin (like a lot of fellas who apprenticed under Boots Obermyer) but he did work for a few years under Jeff Kolbe at Border Barrels in Scotland.

    Buttoned and hammer-forged combat barrels do not meet the long-term precision standards of the cut-rifled tubes. The spec acceptance difference between SOCOM and Army weapons and barrels is the number of precision and stoppage-free rounds fired through the complete weapon.
     
    #12
    sinister said:
    J.R. makes the cut-rifled barrels at Knight's. I can't remember if he started in Wisconsin (like a lot of fellas who apprenticed under Boots Obermyer) but he did work for a few years under Jeff Kolbe at Border Barrels in Scotland.

    Buttoned and hammer-forged combat barrels do not meet the long-term precision standards of the cut-rifled tubes. The spec acceptance difference between SOCOM and Army weapons and barrels is the number of precision and stoppage-free rounds fired through the complete weapon.
    Click to expand...
    Closest I lived to Wisconsin was when once I was a yooper, but am native SoDak, not to be confused with NoDak. Was more under A&M's methodology/type of tutelage in my formative years at HS than Boots' but he and I met minds during tenure in Scotland, when we introduced proper 5R to Europe. Hit it off right off the bat, we both had milked a lot of cows in our time(none of them bulls). Boots reckoned my arse might be getting frostbit in the cold Scottish winters after 7yrs or so, so recommended to Reed if he wanted to make his barrels in Oby fashion in house get that JR in Scotland. I'll never forgive him, ha!
     
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    #13
    __JR__ said:
    Closest I lived to Wisconsin was when once I was a yooper, but am native SoDak, not to be confused with NoDak. Was more under A&M's methodology/type of tutelage in my formative years at HS than Boots' but he and I met minds during tenure in Scotland, when we introduced proper 5R to Europe. Hit it off right off the bat, we both had milked a lot of cows in our time(none of them bulls). Boots reckoned my arse might be getting frostbit in the cold Scottish winters after 7yrs or so, so recommended to Reed if he wanted to make his barrels in Oby fashion in house get that JR in Scotland. I'll never forgive him, ha!
    Click to expand...
    Very cool. Thanks for posting sir. Btw, A&M? Who is that?

    ETA: ohh I think youre saying you learned cut rifling barrels at HS Precision??
     
    #17
    Forgetful Coyote said:
    Would you say yall's cut rifled chrome lined barrels are more precise/consistent than your CHF chrome lined?
    Click to expand...
    Chrome is a fickle beast. You spend all that time getting the surface finish you want, geometry just how you like it, uniform end to end, nice sharp crown, smooth throat. Then you send it to chrome and cross your fingers, as they etch that nice bore surface out and remove all your edges, enhance any minor roughness then throw a bunch of cracky hard plating over the top to seal it in haha, then throw it in the oven for a bit to cure and HE..Drives a match barrelmaker mad..But it's a necessary evil for the application.

    JR
     
    #18
    Primus said:
    Is krieger still making the LPR barrels or are they in house now as well?
    Click to expand...
    Our goal is to be capable to produce everything we offer in house, but also keeping in mind the years we have developed very good relationships with our high end vendors who supply us with quality top notch product. LPR isn't a huge percentage of our overall production by any means, so it's not the top of the list to 'absorb'.

    JR
     
    #19
    __JR__ said:
    Chrome is a fickle beast. You spend all that time getting the surface finish you want, geometry just how you like it, uniform end to end, nice sharp crown, smooth throat. Then you send it to chrome and cross your fingers, as they etch that nice bore surface out and remove all your edges, enhance any minor roughness then throw a bunch of cracky hard plating over the top to seal it in haha, then throw it in the oven for a bit to cure and HE..Drives a match barrelmaker mad..But it's a necessary evil for the application.

    JR
    Click to expand...
    All things being equal though.. would it be accurate to say the cut rifled blank is starting out at a higher level of precision/quality than the CHF blank, and therefore should still be a more precise/higher quality barrel after chroming than the CHF barrel?
     
    #21
    Forgetful Coyote said:
    All things being equal though.. would it be accurate to say the cut rifled blank is starting out at a higher level of precision/quality than the CHF blank, and therefore should still be a more precise/higher quality barrel after chroming than the CHF barrel?
    Click to expand...
    Let's back up a bit, because I'm interested in your premise, or rather where it derives. Why would you think a cut rifled blank starts out at a higher level of 'precision' than a CHF blank?
     
    #22
    because a machinist lovingly moves the cutter through pass after pass, gently receiving the excess metal until near nirvana is achieved as opposed to a monkey shoving a rod down a pipe with a hole in it and turning on the hammers.

    How'd I do?
     
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    #23
    __JR__ said:
    Let's back up a bit, because I'm interested in your premise, or rather where it derives. Why would you think a cut rifled blank starts out at a higher level of 'precision' than a CHF blank?
    Click to expand...
    Is my premise mistaken? I'd assume that with equal amounts of QC, youd likely end up with equal qaulity in the finished barrels. But as FatBoy kinda mentioned, I'd assume by the nature of the processes, cut rifling will have a higher level of QC and generally more care taken.. Yall aint putting CHF barrels on your LPR, nor any of your SR25 models which obviously are a bit more focused on longer range precision.. I'd think theres a reason for that?
    Perhaps my wording was a bit off. Certainly hammer forges can produce barrels with very consistent dimensions, but I doubt they're more dimensionally consistent than cut rifled tubes, and will have a ton of induced stress in the blanks which the cut barrels will not.
     
    #24
    Fatboy would also mention Ive got a lot of mileage in the industry as well as the barrelmaking gig. So I say the premise might be premature. If the forging is done in house we can take equal amounts of QC. We can control the material, the bore dimensions and geometry, the stress relief, if done in house. Yes you can't argue with the cut rifling quality, but ask yourself has anyone addressed cold hammer forge production with a cut rifling mentality? Probably not. yet.
     
    #31
    I had an FN SPR once. I shot ten rounds of FGMM into about 3/4” while lying on gravel in the rain using a sweatshirt as a rear bag. It was my second sub MOA group ever. That was a hammered and chrome lined barrel.
     
    #32
    No doubt, I really wanna get me a FN SPR. Shows what can be done with the right quality control. Not sure how true it is, but I've heard that for the HK PSG1, HK used the barrels which came off the forge not needing any straightening/the barrels that were already straight. The ones that needed straightening were used elsewhere.
     
    #36
    The Sr15 has a proprietary barrel extension to work with the E3 bolt. You can run a normal bolt in an E3 extension but it's more for emergencies then long term use. You also loose the advantages of the E3 in the first place. So Sr15 barrels will not fit or work in a mil spec gun if that makes sense. If only KAC would sell the SR15 barrel extension it would open up a world of amazing opportunities. They could make more money from selling componets than full guns.
     
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    #38
    Forgetful Coyote said:
    Did the M110K1 have a chrome lined barrel? Also, will SR15 barrels fit standard mil spec ARs?
    Click to expand...

    I am a Mk11 and M110 afficiando. Not so much on the K1. I am not aware of any chrome-lined M110s. Chrome-moly barrels, yes. Could I be wrong on the K1? Yes, but have not heard that.
     
    #41
    sharfshutz762 said:
    JR..can you tell me if the cur 5R chrome lined KAC barrels you make are a tighbore or what the bore ends up being after chrome. .299?

    Thank you also for sharing some of your history with us.
    Click to expand...
    I can tell you the CR chromed barrels post chrome meet the same bore spec as the non chromed. Maybe I'm just too cheap, simple minded, or lazy to buy or set up 2 more air gages to measure the same dang bore just because it's chromed haha..
     
    #42
    FatBoy said:
    because a machinist lovingly moves the cutter through pass after pass, gently receiving the excess metal until near nirvana is achieved as opposed to a monkey shoving a rod down a pipe with a hole in it and turning on the hammers.

    How'd I do?
    Click to expand...
    I was near Nirvana back in '94, then he shot himself. Production is about the monkey setting up the tool that the other monkey designed. Precision is a deeper monkey that often requires more attention to detail, but is still slave to the tool that the other monkey designed. I do both. So if one understands each process on that deeper monkey level, well he might just have an idea or two, from the two, that could make a difference ..
     
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