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View Full Version : MRP 18" SS vs. custom SPR upper



QuietShootr
03-15-12, 09:31
OK - tired of ****ing around with guns that won't shoot.

I'm looking for a no-shit half-minute or better upper. Would it be better to have ADCO or BCM build me a Mk12-style upper, or will the MRP with the 18" 1:7 barrel do what I need to do? I would prefer the monolithic upper, all other things being equal, but if the gilt-edge accuracy isn't there with that barrel then I can go another way.

ASH556
03-15-12, 09:59
Larue? Aren't they supposed to have an accuracy guarantee?

a0cake
03-15-12, 12:51
OK - tired of ****ing around with guns that won't shoot.

I'm looking for a no-shit half-minute or better upper. Would it be better to have ADCO or BCM build me a Mk12-style upper, or will the MRP with the 18" 1:7 barrel do what I need to do? I would prefer the monolithic upper, all other things being equal, but if the gilt-edge accuracy isn't there with that barrel then I can go another way.

Man, that's a pretty tall order. My BCM MK12 is in the arena but it's a 1/2 - 3/4 MOA gun. Hell, my real MK12 was a 3/4 to 1 MOA gun (although that was probably due to being limited to MK262).

The BCM SS410 barrels are great, but if you are looking for ultimate accuracy, you really need to look at an actual match grade barrel, which even BCM, Noveske, etc., do not offer.

If you have the money and don't mind waiting on a custom barrel, talk to the guys at Krieger ( http://www.kriegerbarrels.com/ ) about what you're looking for and figure out a contour. The BCM SS410 contour is great for a tactical rifle, but if you want absolute accuracy you'll need to go a bit heavier, especially with an 18'' barrel.

Once you get the barrel in hand, mate it to a VLTOR VIS, Ranier Ultra Match Billet Upper, or a Larue Billet upper and you should be in business.

Apricotshot
03-15-12, 14:51
I have the Rifle lenght MRP with the 18 inch SS barrel. I've had rifle out at a local FL SPR shoot about a year ago. It performed, accuracy wise, very similar to "correct" Mk12 clone rifles built by the usual names in the SPR biz (Wes of MSTN, ADCO and some others that I cannot recall). There was one competition where we had the best 10 shot group at 100 yds. This was a group of at least 30 rifles. All of the groups were very close to each other and it was more user error that prevented a better showing on my part. I was satisified with the hardware's performance.

I don't know if you are trying to build a clone or not though. i.e OPS Inc break and collar, correct gas block....so on and so forth. The LMT is not that.

TehLlama
03-15-12, 15:15
If you've already got the MRP upper, the 18" SS barrel will do it. Spend the rest on whichever match trigger works best for you (SSA-E comes to mind).

If you're looking at a whole new upper - Any of the BCM, Noveske, Centurion, HighCaliberSales, or ADCO units will do, and 18" or 16" are viable options. The Centurion and HCS are a pretty beefy barrel, but it's not the thickest setup, just a medium contour compromise for tactical use with some accuracy.

As far as twist rate, I haven't seen anything conclusive to be concerned with 1:7 or 1:8, as far as the other parts, the LT Upper, RA Ultramatch, or MUR-1A all come to mind, and I'd probably toss a DD handguard on there (a long Lite rail or RIS-II M4).

I have a thicker contour 16.5" Douglas barrel from ADCO - it keeps up with the Mk12 Centurion upper I have for accuracy, and I don't think 77gr .223 pressure BH is that upper's favorite load. It may be worth considering the shorter barrel if you're not pushing it past 600m ever, or aren't as concerned about wind over hundreds of yards, since the shorter barrel is a more rigid one.

a0cake
03-15-12, 15:20
I didn't realize you already had the MRP upper (do you?) Isn't there a place that will take standard barrels and convert them to work on the MRP? If so, seems like having that done to a Krieger would be an optimal solution.

d90king
03-15-12, 15:21
Man, that's a pretty tall order. My BCM MK12 is in the arena but it's a 1/2 - 3/4 MOA gun. Hell, my real MK12 was a 3/4 to 1 MOA gun (although that was probably due to being limited to MK262).

The BCM SS410 barrels are great, but if you are looking for ultimate accuracy, you really need to look at an actual match grade barrel, which even BCM, Noveske, etc., do not offer.

If you have the money and don't mind waiting on a custom barrel, talk to the guys at Krieger ( http://www.kriegerbarrels.com/ ) about what you're looking for and figure out a contour. The BCM SS410 contour is great for a tactical rifle, but if you want absolute accuracy you'll need to go a bit heavier, especially with an 18'' barrel.

Once you get the barrel in hand, mate it to a VLTOR VIS, Ranier Ultra Match Billet Upper, or a Larue Billet upper and you should be in business.

Do you not like the Rock barrels? I have seen some pretty impressive groups out of them but this is your area of expertise so I'm curios what you don't like about them.... I was under the impression that his barrels where highly regarded in the precision arena.

My standard MRP barrel is an inch or slightly better with 69gr SMK's...

QuietShootr
03-15-12, 15:24
I didn't realize you already had the MRP upper (do you?) Isn't there a place that will take standard barrels and convert them to work on the MRP? If so, seems like having that done to a Krieger would be an optimal solution.

No, I don't have the upper. I was just thinking all other things being equal the MRP would be easier to get the same end result.

a0cake
03-15-12, 15:26
Do you not like the Rock barrels? I have seen some pretty impressive groups out of them but this is your area of expertise so I'm curios what you don't like about them.... I was under the impression that his barrels where highly regarded in the precision arena.

My standard MRP barrel is an inch or slightly better with 69gr SMK's...

Are the Rock barrels for the LMT MRP's the cut rifling match grade barrels or the pull buttoned OEM production grade barrels? There's a difference. It's the same thing as the difference between Krieger and its sister company Criterion (BCM SS410). If they are in fact the cut rifled match barrels, or if those barrels can be fitted to an MRP, I'd call that a great solution also. I don't own an MRP nor do I have a ton of trigger time, but they are clearly accurate guns. My recommendation wasn't a condemnation of the MRP at all. I've just traditionally used Krieger and its my first instinct to go that route when going for accuracy above all else.

ICANHITHIMMAN
03-15-12, 17:59
OK - tired of ****ing around with guns that won't shoot.

I'm looking for a no-shit half-minute or better upper. Would it be better to have ADCO or BCM build me a Mk12-style upper, or will the MRP with the 18" 1:7 barrel do what I need to do? I would prefer the monolithic upper, all other things being equal, but if the gilt-edge accuracy isn't there with that barrel then I can go another way.

Did you try handloading for the barrel you already have.

rushca01
03-15-12, 18:02
I'm sure trident will come along shortly but I can't think of anyone else that knows more about LMT and has done more accuracy testing then anyone else with the MRP.

QuietShootr
03-15-12, 18:09
Did you try handloading for the barrel you already have.

Oh, yeah. Suffice it to say if I had hair I would have torn it out by now.

TAZ
03-15-12, 18:42
I have an ADCO built Mk12 Mod1 clone (WOA barrel and parts) and it's a great shooter. It is MOA capable using 75gr Hornady Steel Match and sub MOA with 77gr GMM ammo. It is slightly above MOA with 75gr Horn Practice ammo and 75gr Priv. I'm pretty sure that with someone competent behind the trigger it can do more, but at this time that's the best I can do. So I wouldn't hesitate to recommend one of his builds. Have no experience with the MRP so I can't comment there, aside from I'd like one.

ICANHITHIMMAN
03-15-12, 19:55
Oh, yeah. Suffice it to say if I had hair I would have torn it out by now.

Well thats fustrating! What bullet were you using? I wish you lived closer I would love to help.

Jon

QuietShootr
03-15-12, 20:12
Well thats fustrating! What bullet were you using? I wish you lived closer I would love to help.

Jon

The latest one that's pissing me off is that FN I just got. I'm about to give up on boltguns entirely, which is why this post.

(and before anyone goes there - it isn't my shooting. I have had several other guys shoot this gun, last time was yesterday. We both fired 5-round bug holes at 100 with 175gr Black Hills with my friend's gun, then we both fired shotgun-style 1"+ groups with the FN. I know it has a guarantee, but this is my fourth suck-ass boltgun in 12 months. I'm tired of it and don't want to **** around with it.)

a0cake
03-15-12, 20:26
The latest one that's pissing me off is that FN I just got. I'm about to give up on boltguns entirely, which is why this post.

(and before anyone goes there - it isn't my shooting. I have had several other guys shoot this gun, last time was yesterday. We both fired 5-round bug holes at 100 with 175gr Black Hills with my friend's gun, then we both fired shotgun-style 1"+ groups with the FN. I know it has a guarantee, but this is my fourth suck-ass boltgun in 12 months. I'm tired of it and don't want to **** around with it.)

Sucks to hear man, especially with the high hopes for the FN. Are you going to send it back and see what they say at least?

QuietShootr
03-15-12, 20:30
Sucks to hear man, especially with the high hopes for the FN. Are you going to send it back and see what they say at least?

I don't think so. I think I'm just going to get rid of it to somebody who is willing to go through all the bullshit of sending it back and forth. I'm going to sell the scope too, because while I don't THINK it's the problem, it's been on three of the four shitty rifles so I've lost confidence in it.

ICANHITHIMMAN
03-15-12, 20:47
I got an Idea send me the rifle and I will build you a load for it. What does your 200M group look like? Send me a PM and we will talk about it.

QuietShootr
03-15-12, 21:08
You know, that's a hell of a nice offer that I'd take you up on if I hadn't had some absolute geniuses working on loads for it for the last couple of months. We've tried RL-15, Varget, 4064, Federal 210Ms, CCI BR2s, Federal standard, 178gr AMAX, 168SMK, 175SMK, 155gr Palmas, moly, non-moly, Winchester brass, Federal match brass, Lake City LR brass, Lapua brass, Federal 7.62 match brass, and experimented with COALs from 2.750 to 3.010 and all kinds of shit in between. Plus the loads were assembled on a Redding T-7 press with Redding micrometer dies, each charge being hand-weighed (not thrown with a measure), primer pockets and flash holes uniformed, and both neck and FL sizing.

I am about out of shit I might have missed.

C-grunt
03-15-12, 21:31
You know, that's a hell of a nice offer that I'd take you up on if I hadn't had some absolute geniuses working on loads for it for the last couple of months. We've tried RL-15, Varget, 4064, Federal 210Ms, CCI BR2s, Federal standard, 178gr AMAX, 168SMK, 175SMK, 155gr Palmas, moly, non-moly, Winchester brass, Federal match brass, Lake City LR brass, Lapua brass, Federal 7.62 match brass, and experimented with COALs from 2.750 to 3.010 and all kinds of shit in between. Plus the loads were assembled on a Redding T-7 press with Redding micrometer dies, each charge being hand-weighed (not thrown with a measure), primer pockets and flash holes uniformed, and both neck and FL sizing.

I am about out of shit I might have missed.

Holy shit. Can't say you didn't try. Good luck with your quest. Any thoughts about rebarreling the FN with a match barrel? I'm all for Mk12s and SASSs but I think the bolt still has an edge in accuracy.

QuietShootr
03-15-12, 21:41
Holy shit. Can't say you didn't try. Good luck with your quest. Any thoughts about rebarreling the FN with a match barrel? I'm all for Mk12s and SASSs but I think the bolt still has an edge in accuracy.

I'm not paying $800 to rebarrel a $2600 gun that has a factory guarantee of .5MOA. Piss on it. It's already been back to FN once and they recrowned it and pronounced it fixed.

ICANHITHIMMAN
03-15-12, 21:54
WOW ok dont think I can help much then. Did you check the mag box for binding, lap the lugs, bed the scope base, etc hows that crown look. It sounds like the handload is not going to help. What was it printing at 200plus?

QuietShootr
03-15-12, 22:10
WOW ok dont think I can help much then. Did you check the mag box for binding, lap the lugs, bed the scope base, etc hows that crown look. It sounds like the handload is not going to help. What was it printing at 200plus?

Best I was able to get was about 1 3/4", but not reliably. I could get behind that with a shit-ass factory 700, but an A3G doing that is ****in ridiculous.

and yes, base is bedded.

The_War_Wagon
03-15-12, 22:24
I had Kevin Johnson, of Johnson Tactical Rifles build me a Mk.12 tackdriver last year, to do this very thing. Sadly, he took a PAYING job in Seattle last August, and got out of the custom rifle building business. :(

Have you looked INTO having a custom, one-off, upper professionally built? It ain't cheap, but you GET results!

ALCOAR
03-15-12, 22:25
Are the Rock barrels for the LMT MRP's the cut rifling match grade barrels or the pull buttoned OEM production grade barrels? There's a difference. It's the same thing as the difference between Krieger and its sister company Criterion (BCM SS410). If they are in fact the cut rifled match barrels, or if those barrels can be fitted to an MRP, I'd call that a great solution also. I don't own an MRP nor do I have a ton of trigger time, but they are clearly accurate guns. My recommendation wasn't a condemnation of the MRP at all. I've just traditionally used Krieger and its my first instinct to go that route when going for accuracy above all else.

RE: MRP/MWS factory barrels Fall 2004-2011 (I stop at 2011 because the Rock/LMT relationship is so far beyond sketchy it's not even funny)

Since the inception of the MRP platform in the fall of 2004, all production factory MRP barrels have been made by contract for LMT by Mike Rock/Rock Creek barrels.

This includes all CL/SS, calibers, lengths, and D.I./Piston.

You are indeed correct that there is two distinct different grade of barrels put out by Rock Creek....

1. 5 and 6 groove OEM production grade barrels in both stainless and chrome moly. These barrels are pull buttoned with leader bar equipped machines, stress relieved and inspected for uniformity. Available in quantity

Examples of these barrels in the MRP and now MWS lineup would be all the CL model barrels.

2. Single point cut rifled barrels are manufactured on twin spindle hydraulic Pratt & Whitney rifling machines and are available in 5R or 7R rifling profiles. All barrels are hand lapped to superb interior finishes.

Examples of these barrels in the MRP and now MWS lineup were in the past every single SS model made for the MRP platform, and all the .308 5R SS MWS barrel options...16" SST(L129A1 barrel), 18" 5R SS, 20" 5R SS.

Here is my MRP Recce, and MRP SPR with the cut rifled SS barrels...

http://i888.photobucket.com/albums/ac81/trident1982/DSC00616-1.jpg
http://i888.photobucket.com/albums/ac81/trident1982/DSC00600-1.jpg



I'm sure trident will come along shortly but I can't think of anyone else that knows more about LMT and has done more accuracy testing then anyone else with the MRP.

Thanks for the nod pal, if the OP wants any of my reports and the like on the MRP 16" or 18" 5R SS 5.56 barrels, I'll post a bit more on the topic.

QuietShootr
03-15-12, 22:28
All right, I'm calmed down a little bit. I'm going to have my dealer ship it to FN service and tell them not to send it back until it's a ****ing half-minute gun like they promised.

ICANHITHIMMAN
03-15-12, 22:47
All right, I'm calmed down a little bit. I'm going to have my dealer ship it to FN service and tell them not to send it back until it's a ****ing half-minute gun like they promised.

Ya you paid for it you should get it. I have the cheep 500$ barreld action fron CDNN and it will cut that in half at 200M.

a0cake
03-15-12, 23:29
Examples of these barrels in the MRP and now MWS lineup were in the past every single SS model made for the MRP platform, and all the .308 5R SS MWS barrel options.


Thanks for the clarification on the LMT/Rock barrels. So what's the current deal? If somebody was to order a brand new SS barrel for their MRP, what would they get?

ALCOAR
03-15-12, 23:57
My pleasure, in regards to the very newest 5.56 SS MRP barrels....up until about a week or two ago I thought same old, same old in regards to them being the same as all of the past 5.56 SS barrels including my very own....which were of the uber accurate Rock Creek cut rifled 5R SS variety. No concrete info on this specific area, however it's just another proverbial brink in the wall....and one more mouse's wisper:)

I have been trying my ass off for almost a full year now to get any little bit of clarity on this HUGE issue in my book from the source...LMT. No shit, every time I get a reply back it's incredibly mind pondering, and useless in terms of getting a direct answer to my direct questions.

Bear in mind that I've never had them refuse to answer one of my many thousands of questions, more over I'm quite often given privileged/secret crumbs here and there.

LMT as some may know like to build damn near everything in house due to their exceptional facilities, and machining abilities. The MRP/MWS barrel lineup has turned out to be one helluva huge amt. of different barrels that LMT doesn't make in house, and ultimately LMT can't like this position of there's. It only makes sense for LMT to make a cut rifled match grade blank in house for the MRP/MWS lineup, and ultimately all the other MRP/MWS barrels in the future.

I'll end here....

1.) LMT assures me every single time that if Rock gets dropped, the replacement must be every bit as accurate....and that's just Karl Lewis's policy I've found out. So ultimately I trust enormously LMT's future plans for the MRP/MWS barrel lineup with...or without Rock barrels.

2.) Kinda makes you wonder if LMT is going to be getting directly into the match grade cut rifled barrel game...:eek::p

ICANHITHIMMAN
03-16-12, 11:10
My pleasure, in regards to the very newest 5.56 SS MRP barrels....up until about a week or two ago I thought same old, same old in regards to them being the same as all of the past 5.56 SS barrels including my very own....which were of the uber accurate Rock Creek cut rifled 5R SS variety. No concrete info on this specific area, however it's just another proverbial brink in the wall....and one more mouse's wisper:)

I have been trying my ass off for almost a full year now to get any little bit of clarity on this HUGE issue in my book from the source...LMT. No shit, every time I get a reply back it's incredibly mind pondering, and useless in terms of getting a direct answer to my direct questions.

Bear in mind that I've never had them refuse to answer one of my many thousands of questions, more over I'm quite often given privileged/secret crumbs here and there.

LMT as some may know like to build damn near everything in house due to their exceptional facilities, and machining abilities. The MRP/MWS barrel lineup has turned out to be one helluva huge amt. of different barrels that LMT doesn't make in house, and ultimately LMT can't like this position of there's. It only makes sense for LMT to make a cut rifled match grade blank in house for the MRP/MWS lineup, and ultimately all the other MRP/MWS barrels in the future.

I'll end here....

1.) LMT assures me every single time that if Rock gets dropped, the replacement must be every bit as accurate....and that's just Karl Lewis's policy I've found out. So ultimately I trust enormously LMT's future plans for the MRP/MWS barrel lineup with...or without Rock barrels.

2.) Kinda makes you wonder if LMT is going to be getting directly into the match grade cut rifled barrel game...:eek::p

Alex
Im with you brother I love my MRP but when I speek to Gean on the phone I'm left with a sinking felling :confused:

2ac
03-18-12, 13:07
I've been very pleased with my Centurion Arms built DMR/SPR. It uses a VLTOR VIS 3 and their SPR barrel. And it may still be on sale.

Vash1023
04-14-12, 09:59
i live down the street from adco.

steve might not be the best at customer "service", but he's by far the best at customer "satisfaction"

ive never heard of a single instance of someone not being happy with any of his work.

Biz Kizzle
05-24-12, 10:57
All right, I'm calmed down a little bit. I'm going to have my dealer ship it to FN service and tell them not to send it back until it's a ****ing half-minute gun like they promised.

don't mean to bring up an old thread but...

Just wondering if FN ever followed through on anything?

I got pissed at FN just reading this thread haha i can't imagine how you feel about getting an accuracy guarantee and being failed multiple times.

i would have sold the scope too..


on the AR side of things, i think you could build a 1/2" upper with the right parts and handloading. people already hit on the components.

the MRP doesn't come to my mind when i think precision AR uppers, but Trident makes a good case for his set up.

ra2bach
05-24-12, 13:19
The latest one that's pissing me off is that FN I just got. I'm about to give up on boltguns entirely, which is why this post.

(and before anyone goes there - it isn't my shooting. I have had several other guys shoot this gun, last time was yesterday. We both fired 5-round bug holes at 100 with 175gr Black Hills with my friend's gun, then we both fired shotgun-style 1"+ groups with the FN. I know it has a guarantee, but this is my fourth suck-ass boltgun in 12 months. I'm tired of it and don't want to **** around with it.)

not to further your agony but the FN is really sensitive to receiver screw tension. I assume you have or can find this info but have you put a torque wrench on these?..

WhiteBear556
07-07-12, 14:17
I agree i have both the MRP and MWS. LMT needs to start turning out there own barrels in house, then they could have control of everything. Not saying my rocks are no good there great. I would also like to see them offer a cold hammer forged barrel like everyone else is as well.

Peace

ALCOAR
07-07-12, 15:34
Appropriate time for this thread to get bumped....

After running thousands of rounds over 2+yrs with my MRP SPR w/ Rock 5R SS 18", I recently got an opportunity I couldn't refuse to put together an "uber" SPR upper.....time will be the judge.

The new SPR consists of:

Vltor MUR 1A
Geissele SMR 15"
Geissele "in house" 18" match SS SPR barrel

http://www.youtube.com/watch?v=uJPAQSjaBLg

http://i888.photobucket.com/albums/ac81/trident1982/DSC07101-1.jpg

MRP SPR
http://i888.photobucket.com/albums/ac81/trident1982/DSC03348-1.jpg

gamewarden
07-08-12, 22:54
Do you have the specs on the Geissele barrel? Do you know where the blank is from?

On a side not how does the KAC lower fit with the Vltor MUR 1A? I was thinking of getting either the KAC lower or Noveske Gen II to go with my MSTN SPR build w/MUR 1A upper.

thanks

ALCOAR
07-09-12, 00:35
In regards to the barrel...I didn't press for to much info on them, so I can't say for certain whom make the blanks for GA.

Knowing Geissele, there's only a cpl. of candidates that they would use. The specs are .223 Wylde 1:7 18".

http://i888.photobucket.com/albums/ac81/trident1982/DSC06556-1.jpg
http://i888.photobucket.com/albums/ac81/trident1982/DSC06526-1.jpg
http://i888.photobucket.com/albums/ac81/trident1982/DSC06548-1.jpg
http://i888.photobucket.com/albums/ac81/trident1982/DSC06536.jpg

In regards to the MUR-KAC hookup....pretty tight fitting. That stuff is usually a case by case basis though I've found.

JFArmsCo
07-09-12, 08:47
that contour looks an awful lot like BCM's SS410 contouring...

gimpy
07-11-12, 19:54
I'm in the same boat except I already have a LMT. I'm wondering if I should get the stainless barrel or get a PRI upper. I'm looking for a good excuse to add to my collection, but realize that I could look into getting an FN SPR... Kinda worried about that after reading this thread.

decodeddiesel
08-01-12, 00:07
I just wanted to say, I have really enjoyed this thread. I was not that familiar with the actual way in which rifling is formed (or cut) into a precision barrel. This is especially fascinating being a mechanical engineer who is into manufacturing engineering.

eesmith4
08-08-12, 16:24
some info on 5.56 ss LMT/rock creek barrels...

I ordered a 16" SS 5.56 barrel for my LMT MRP, and I received it last friday. Upon examination I noticed it was a 6 groove barrel, and called LMT to find out if 5R barrels were available. I was told that all current SS barrels are 6 groove 1/7 button rifled, and as far as the tech knew they had always been that way for as long as he had been there.

I then called rock creek, they told me that all current production 5.56mm blanks sent to LMT are 6 groove button rifled. (They only ship them blanks, LMT does the chambering, contouring, gas port drilling, etc)

I asked about past 5R cut rifled 5.56mm production, the guy told me he was aware of a few that had been made, but all current 5.56mm production for them was 6 groove button rifled.(SS MWS 7.62mm is still 5R cut rifled)

So in short, you order a SS 5.56 MRP barrel today, you'll get a standard 6 groove button rifled like me.

ETA: my barrel is marked "MP SPR 1/7 SS" like the others in this thread, only difference is it's marked behind the gas block so it's under the rail when installed. I'd take a pic but I'm offshore ATM.