"Best" Semi-Auto Precision Rifle

daved

Full Member
Mar 28, 2013
121
7
18
Las Vegas, NV
#1
I know this may be like Silverado vs F150 or Bud vs Coors but I'm interested in adding a 6.5CM/308 semi-auto precision rifle to my bolt action guns. I'm sure this question has been asked before but I'd like any input into what constitutes the "best" semi-auto PR in terms of accuracy, ergonomics, reliability, ease of maintenance, etc. Basically something comparable to AI or GAP bolt action rifles, production or custom. Any thoughts would be greatly appreciated--

Thanks,

Dave
 
Likes: Stevo3556
Jun 11, 2017
187
46
28
#4
An AR10 that you custom build exactly the way you want it, hand picking parts that taylor to your budget, taste, and intended use.

Very high end AR10 > AI, Gap, Surgeon, TRG, Cadex, High end custom, Everything else
 

Rudy Gonsior

Breaker of Things
Jan 3, 2018
248
156
43
Maine
ridgelineshooting.com
#6
As a precision Rifle/Sniper instructor for the last few years I can tell you out of all the large frame guns I've seen LaRue, Knights and JP are the top performers in terms of accuracy and reliability. The LMT MSW has also gotten some good reviews from guys like Caylen Wojcik, I've seen a few come though but not enough to say. I would not recommend building a large frame, I mean just about anybody can slap together small frame AR's and shot sub MOA with the right ammo but the results with large frame AR's tend to be less then stellar. Sure you'll see people posting how they build a sub MOA budget AR10 for $1500 and thats great but your results may vary, and next thing you know your budget/dream rifle turns into a $3000 money pit.

The other end to this is convo is the skills of the shooter. Frankly large frame gas guns tend to be fussy in the accuracy department, proper fundamentals are important to get the most out of a gas gun. Errors that you typically can get away with while running a bolt gun tend to exaggerate when a shooter steps up to a large frame AR. If you want to run a gas gun well consistently, you have to put in the hours to get the most out of it but again if you start with a shit gun it's never going to get better.
 

daved

Full Member
Mar 28, 2013
121
7
18
Las Vegas, NV
#9
Thanks, guys - I appreciate your on-point comments and suggestions. Having spent most of my rifle days with bolt action guns, I had no idea that some of these companies made semi-autos.

One thing that struck me - it looks like all the rifles mentioned are DI rather than gas piston which I thought had pretty much become the norm in AR type rifles. What's the reason the PR semi-autos use the older DI system?

Also, I'm familiar with a number of smiths who are known to produce superb bolt-action guns. I assume there are similar names in the semi- auto world. Who would they be?

Rudy - thanks for comments on technique. I was curious about one thing - is the reciprocating mass the factor that makes semi-autos more difficult to shoot accurately?
 

The King

Showercookie Monster
Sep 17, 2004
988
222
43
Denver, Colorado
#12
raw accuracy caused the piston to bounce in the big frame world. Especially since the earliest piston Big gun (Lwrc repr) was sort of a lemon.

That and they run cleaner than a small frame AR - even the suppressed big guns I have run usually run only as dirty as a small ar

I have built dozens of big guns and owned all of the Big name ones. I was an instructor at a school specializing in gas guns - the JP LRP-07 was probably my favorite of the big guns. I would not build one again.
 
Jan 9, 2018
5
0
1
#14
Sr25 here with H 24'' brl. Smooth action and crisp trigger. Bought mine years ago and boxed it in storage. Been thinking of scoping her this summer and finally giving her some exersize.
 

AMP!

Three sheets to the wind
Feb 17, 2017
609
14
18
#16
I’ve shot a few and so far the JP LRP-07 is hands down the best. I haven’t been behind a gap, but after getting my JP, I no longer lust for a GAP or the like.

I’ve also let friends shoot the JP a few times and they instantly fall in love with it.

That being said, I may be selling it to go back to a custom bolt. Unfortunately I can not afford more than one higher end rifle right now, and I really my bolt gun.
 
Likes: Stevo3556

Rudy Gonsior

Breaker of Things
Jan 3, 2018
248
156
43
Maine
ridgelineshooting.com
#18
Thanks, guys - I appreciate your on-point comments and suggestions. Having spent most of my rifle days with bolt action guns, I had no idea that some of these companies made semi-autos.

One thing that struck me - it looks like all the rifles mentioned are DI rather than gas piston which I thought had pretty much become the norm in AR type rifles. What's the reason the PR semi-autos use the older DI system?

Also, I'm familiar with a number of smiths who are known to produce superb bolt-action guns. I assume there are similar names in the semi- auto world. Who would they be?

Rudy - thanks for comments on technique. I was curious about one thing - is the reciprocating mass the factor that makes semi-autos more difficult to shoot accurately?
I think that larger amounts of reciprocating mass makes them tricker than the small frame systems. Basicly all gas guns but even more so with the large frame, you have a recoil impulse broken into 3 components. The first, just like the bolt gun, appears when the cartridge is fired. The second component appears as the bolt of a gas gun is unlocked and slams to the rear extracting and ejecting the spent case. The final phase is the impulse of the bolt returning forward feeding, chambering and locking.

Now a lot of things can happen in that cycle of operations and the whole key to successes is to do all of that constantly. Any change the forces at play, whether shooter induced like poor body position or improper follow thought at one of those points can have significant impact on the constancy of which the next round is chambered. Looking at the mechanical side of things, even difference in spring tension of a loaded magazine vs. empty magazine against the bottom of the bolt carrier can cause accuracy issues.

Again, your adding more mass and more energy with the large frame system, getting it to work right to produce accuracy and reliability in an individual rifle can be time consuming (or sometimes you luck out) but the real challenge for an manufacturer is coming up with a recipe that can produce the same results across the board. Thats where companies like JP, Knights and LaRue standout, they each have their recipes for what works. Knights tend to sacrifice a bit of that top end accuracy for reliability in extreme environments. JP is hands down the most consitanly accurate gas gun but run it hard in the dirt and grim and you might choke it. And LaRue seem to run some where in between the two.

Back to gas gun mechanics though beyond reciprocating mass there are some key design differences between bolts and gas guns. Specifically, we are looking at lock time, the time between the break of the trigger and cartridge ignition. With bolt guns once cocked and locked, things get pretty simple. The typical trigger groups consist of the trigger (the part your pressing strait and to the rear), this moves an actuator lever, and in which turn engages the sear, which releases the firing pin in order to strike the cartridge primer. Not counting the springs and pins holding everything in place that’s less than a handful of moving parts to make things go bang.

Fewer parts and less movement means a quick lock time. Most bolt actions are clocking in right around 2-4 milliseconds. I know this doesn’t sound like much but given the whole trick to good shooting is to pull the trigger without disturbing the sights, this is critical. Hence, why trigger control is a fundamental of marksmanship, the reality is even a small, nearly unperceivable deviation of the sights during these few milliseconds will cause grouping errors at distance.

Conversely a typical trigger group of a gas gun consist of: the trigger, when pressed this releases the hammer, and in turn, the hammer flies free in long (comparatively speaking) swinging arch and slams the firing pin forward order to strike the cartridge primer. Sounds simple enough right? However, the big catch here is that lock time, because that hammer has to swing all the way around. Naturally covering that extra distance not found in bolt guns eats up a bit more time. In fact, good luck even finding a manufacture who will bother posting their triggers lock time, but on average a good gas gun trigger is going to be double the lock time of a bolt gun.

In a nut shell you can start to see that gas guns deal with the unfortunate reality of physics. For every action you’ll have an equal and oppose it reaction, this simply means gas guns harder to shoot then bolts when precision and accuracy are your goals.
 

daved

Full Member
Mar 28, 2013
121
7
18
Las Vegas, NV
#20
Rudy - thanks for that dissertation on the physics of semi-autos. It's very helpful in understanding the practical aspects of shooting an SA accurately. Where do you do your instructing?

Given the large number of favorable comments on the JP LRP-07, as well as some very positive reviews, I've been looking at their website. Lordy be, the number of various options available are overwhelming - almost like building a custom. So another question to the LPR-07 owners - just which of the available options have you found to be the most valuable to have?

Thanks again for your input--

Dave
 
Last edited:

Greg Langelius *

Resident Elder Fart
Aug 10, 2001
5,497
768
113
Arizona, good place for me...
#22
I like gas impingement mostly because of the smaller amount of gyrating mass involved.

I do all (so far) of my Precision AR shooting off a rest or bipod and bench, and probably don't need the faster lock times from which action shooters would benefit.

I like a factory rifle because it is not a one-off, and has an obligation to provide a trustworthy, reliable implement, time after time.

I like the Stag products, and my sights are set on them for when I want to buy my AR-10 type rifle.

As it happens, I'm not ready yet, and while I may be missing something, I'm not finding a 24" .308 that corresponds to their Stag 15 Varminter.

I have a pair of their Model 6 Super Varminters, just recently superceded by their Stag 15 Varminter. They fit my image of a high volume factory precision AR-15 very nicely; definitely enough, but not too much. Accuracy approaches 1/2MOA at 100yd, and maintenance so far has consisted solely of mundane clean and lube. It shoots to the abilities of its optics, a Mueller 8-32x44 Target Scope, with a 1 Greg handicap.

If I want a 24' 6.5, I'll probably build one using all Stag components hung on a L/W 24" .260 barrel.

Greg
 
Last edited:
Feb 24, 2013
62
6
8
#23
On the jp at least get lmos or vmos.
I like the idea of my thermal dissipator especially on a gun that burns through barrels relatively quick. If you buy one of the packages they offer you usually lose the ability to colorize or modify but the packages have most everything you need and you end up getting a set of $150 rings and $30 bipod rail for the same price or less. I got the dmr package
 

Rudy Gonsior

Breaker of Things
Jan 3, 2018
248
156
43
Maine
ridgelineshooting.com
#24
Rudy - thanks for that dissertation on the physics of semi-autos. It's very helpful in understanding the practical aspects of shooting an SA accurately. Where do you do your instructing?
Dave
Currently I am the director of training and a primary instructor at Ridgeline (https://www.ridgelineshooting.com). Prior to that I was active duty military, spend my last 3 years there as a Special Forces Sniper Instructor out of 1st Special Forces Group.
 
Last edited:

19Scout77

Gunny Sergeant
Jun 9, 2007
3,672
58
48
NJ
#26
Not everything mentioned is DI...the F D Defense is gas piston. I have been shooting one in 308 and 6.5 cm for the last several years and could not be a more pleased.
 
Likes: Jeffd

NET65

Sergeant
Jun 19, 2009
301
8
18
38
TX
#27
I've trained with Ridgeline a couple times when they were under a different name, they're legit. They aren't just regurgitating some out of date material, they're into it, and stay ahead of trends by setting them. I've never trained with or met Rudy, but if he's running with Alex and Dave he's good to go.

Currently I am the directory of training and a primary instructor at Ridgeline (https://www.ridgelineshooting.com). Prior to that I was active duty military, spend my last 3 years there as a Special Force Sniper Instructor out of 1st Special Forces Group.
 
Likes: Rudy Gonsior
Aug 17, 2012
41
4
8
38
#28
In the large platform, a good barrel with a matched bolt, good adjustable gas block tuned to your load, appropriate buffer and spring assembly and a good trigger will probably shoot better than you. Everything else is just a vessel for those parts, for me anyways...
 

Chance

Sergeant
Oct 5, 2004
595
11
18
43
South, TX.
#29
I've trained with Ridgeline a couple times when they were under a different name, they're legit. They aren't just regurgitating some out of date material, they're into it, and stay ahead of trends by setting them. I've never trained with or met Rudy, but if he's running with Alex and Dave he's good to go.
I’m pretty sure that I trained with these guys too, they put on a precision gunfighter class at a TTPOA SWAT conference in Dallas. Great class, and a great bunch of guys!
 
Likes: Rudy Gonsior
Mar 11, 2017
9
2
3
Kentuckyana
#31
I hope you don't mind brother but I'm going to use a lot of this in my justification on upgrading our bolts before going all in on gas guns.

I think that larger amounts of reciprocating mass makes them tricker than the small frame systems. Basicly all gas guns but even more so with the large frame, you have a recoil impulse broken into 3 components. The first, just like the bolt gun, appears when the cartridge is fired. The second component appears as the bolt of a gas gun is unlocked and slams to the rear extracting and ejecting the spent case. The final phase is the impulse of the bolt returning forward feeding, chambering and locking.

Now a lot of things can happen in that cycle of operations and the whole key to successes is to do all of that constantly. Any change the forces at play, whether shooter induced like poor body position or improper follow thought at one of those points can have significant impact on the constancy of which the next round is chambered. Looking at the mechanical side of things, even difference in spring tension of a loaded magazine vs. empty magazine against the bottom of the bolt carrier can cause accuracy issues.

Again, your adding more mass and more energy with the large frame system, getting it to work right to produce accuracy and reliability in an individual rifle can be time consuming (or sometimes you luck out) but the real challenge for an manufacturer is coming up with a recipe that can produce the same results across the board. Thats where companies like JP, Knights and LaRue standout, they each have their recipes for what works. Knights tend to sacrifice a bit of that top end accuracy for reliability in extreme environments. JP is hands down the most consitanly accurate gas gun but run it hard in the dirt and grim and you might choke it. And LaRue seem to run some where in between the two.

Back to gas gun mechanics though beyond reciprocating mass there are some key design differences between bolts and gas guns. Specifically, we are looking at lock time, the time between the break of the trigger and cartridge ignition. With bolt guns once cocked and locked, things get pretty simple. The typical trigger groups consist of the trigger (the part your pressing strait and to the rear), this moves an actuator lever, and in which turn engages the sear, which releases the firing pin in order to strike the cartridge primer. Not counting the springs and pins holding everything in place that’s less than a handful of moving parts to make things go bang.

Fewer parts and less movement means a quick lock time. Most bolt actions are clocking in right around 2-4 milliseconds. I know this doesn’t sound like much but given the whole trick to good shooting is to pull the trigger without disturbing the sights, this is critical. Hence, why trigger control is a fundamental of marksmanship, the reality is even a small, nearly unperceivable deviation of the sights during these few milliseconds will cause grouping errors at distance.

Conversely a typical trigger group of a gas gun consist of: the trigger, when pressed this releases the hammer, and in turn, the hammer flies free in long (comparatively speaking) swinging arch and slams the firing pin forward order to strike the cartridge primer. Sounds simple enough right? However, the big catch here is that lock time, because that hammer has to swing all the way around. Naturally covering that extra distance not found in bolt guns eats up a bit more time. In fact, good luck even finding a manufacture who will bother posting their triggers lock time, but on average a good gas gun trigger is going to be double the lock time of a bolt gun.

In a nut shell you can start to see that gas guns deal with the unfortunate reality of physics. For every action you’ll have an equal and oppose it reaction, this simply means gas guns harder to shoot then bolts when precision and accuracy are your goals.
 
Jan 1, 2014
357
81
28
NoVa
#33
have a les baer monolith swat in 308 with integral compensator/brake that is super accurate. twice i tied for 1st at a local fun match out to 900yds with it and i'm not all that great/experienced. other than sighting it in i haven't shot it for groups, but they guarantee two, five-shot 1/2". their chambers are super tight so i've had to spritz in there after 10-20 rounds. i bought their newer model in 6.5 creed with carbon fiber barrel, but no brake and it's light enough that it jumps around such that i cannot see hits or misses, so sold that.
 

.30kal

Sergeant
Jun 24, 2011
256
32
28
San Jose, CA
#35
What ever brand you end up with, a JP SCS and an Adjustable GB are a must to tweak the timing/lock-up and mitigating as much of the recoil impulse to maximize accuracy. I've personally seen 5 examples of JP barrels and internal components built on Mega MaTen receiver sets and they all shoot lights out. I've also owned a Larue OBR, as well as got behind a Seekins SP10 and LMT. I'd go JP all day and ever day from that sample set.
 
May 3, 2013
141
5
18
#36
I couldn’t justify spending the money on the full jp precision lrp-07 so I bought the most impoparts of it. The barrel/bolt combo with gas block and all moving parts. Put them in an aero precision matched upper and lower with a trigger tech trigger and lancer carbon fiber hand guard. The gun shoots amazing wiTh the only malfunction coming when I adjusted the gas block to low. Love everything about it except the hand guard. It looks amazing but doesn’t tighten up. Has a little slop.
 

Mike 556

Sergeant of the Hide
Jan 31, 2018
514
1,062
93
Northeast PA
#38
Nice build! The Aero matched upper and lower are a heck of a value! What bolt and buffer are you running? When I built mine I tried the Wojtek adjustable gas block, thought that if it didn't work I wouldn't be out a bunch of money. It does everything an adjustable gas block is suppose to do at around 1/3 the cost. Check them out on your next build, you'll be pleasantly surprised! I have no affiliation, just satisfied with the product and service, and Hate overpaying for anything!
Mike
 
Likes: rymart

USMC 308

G14 Classified
Apr 13, 2003
346
97
28
Central TX
#40
When looking for a .223/5.56 precision gas gun....I took several factors into consideration. Was issued a KAC .308....not impressed therefore not in the running for me. Purchased a LaRue Stealth upper to put on a LMT lower with Geissele trigger. The LaRue was better than the KAC but still not satisfied. Sold the LaRue and bougt a JP 20" upper, thermal dissapator.....my search is over. Consistant .5 moa gun with many, many groups better than that. I don't think a more accurate gas gun could be found.
 
Likes: Stevo3556
Apr 1, 2003
895
41
28
42
Indiana
#41
My Armalites with match barrels have always impressed, stupid reliable and damn near as accurate as my custom bolt gun. I took one to a sniper school and I drug it through the mud and shit, it never failed. I also ran it dry suppressed without cleaning or oiling for just 500 round before it started to choke. The cause was build up of carbon under the extractor rim. I removed the carbon and started shooting again with out problems. When I got done with that class I proved a point to myself about the reliability of it and I started regular cleaning and maintenance of it again.
 
Likes: Stevo3556

Steelhead

Sergeant of the Hide
Jun 26, 2003
604
30
28
Idaho
#42
For semi-autos that combine both reliability with accuracy, I've had great results with GAP-10, JP rifles and Rock River Arms, in both small and medium ("AR-15 and "AR-10") sized platforms. Although I've never shot an "AR-15" sized rifle from GAP. Rock River is often overlooked, but their cryogenically treated barrels are top notch. I've shot many a tight group with both their LAR-15 and LAR-8 platforms and both have been very reliable.
 
Nov 10, 2003
57
10
8
69
Somewhere, New Jersey
#43
I think that larger amounts of reciprocating mass makes them tricker than the small frame systems. Basicly all gas guns but even more so with the large frame, you have a recoil impulse broken into 3 components. The first, just like the bolt gun, appears when the cartridge is fired. The second component appears as the bolt of a gas gun is unlocked and slams to the rear extracting and ejecting the spent case. The final phase is the impulse of the bolt returning forward feeding, chambering and locking.

Now a lot of things can happen in that cycle of operations and the whole key to successes is to do all of that constantly. Any change the forces at play, whether shooter induced like poor body position or improper follow thought at one of those points can have significant impact on the constancy of which the next round is chambered. Looking at the mechanical side of things, even difference in spring tension of a loaded magazine vs. empty magazine against the bottom of the bolt carrier can cause accuracy issues.

Again, your adding more mass and more energy with the large frame system, getting it to work right to produce accuracy and reliability in an individual rifle can be time consuming (or sometimes you luck out) but the real challenge for an manufacturer is coming up with a recipe that can produce the same results across the board. Thats where companies like JP, Knights and LaRue standout, they each have their recipes for what works. Knights tend to sacrifice a bit of that top end accuracy for reliability in extreme environments. JP is hands down the most consitanly accurate gas gun but run it hard in the dirt and grim and you might choke it. And LaRue seem to run some where in between the two.

Back to gas gun mechanics though beyond reciprocating mass there are some key design differences between bolts and gas guns. Specifically, we are looking at lock time, the time between the break of the trigger and cartridge ignition. With bolt guns once cocked and locked, things get pretty simple. The typical trigger groups consist of the trigger (the part your pressing strait and to the rear), this moves an actuator lever, and in which turn engages the sear, which releases the firing pin in order to strike the cartridge primer. Not counting the springs and pins holding everything in place that’s less than a handful of moving parts to make things go bang.

Fewer parts and less movement means a quick lock time. Most bolt actions are clocking in right around 2-4 milliseconds. I know this doesn’t sound like much but given the whole trick to good shooting is to pull the trigger without disturbing the sights, this is critical. Hence, why trigger control is a fundamental of marksmanship, the reality is even a small, nearly unperceivable deviation of the sights during these few milliseconds will cause grouping errors at distance.

Conversely a typical trigger group of a gas gun consist of: the trigger, when pressed this releases the hammer, and in turn, the hammer flies free in long (comparatively speaking) swinging arch and slams the firing pin forward order to strike the cartridge primer. Sounds simple enough right? However, the big catch here is that lock time, because that hammer has to swing all the way around. Naturally covering that extra distance not found in bolt guns eats up a bit more time. In fact, good luck even finding a manufacture who will bother posting their triggers lock time, but on average a good gas gun trigger is going to be double the lock time of a bolt gun.

In a nut shell you can start to see that gas guns deal with the unfortunate reality of physics. For every action you’ll have an equal and oppose it reaction, this simply means gas guns harder to shoot then bolts when precision and accuracy are your goals.
Rudy
Your explanation was so easy to follow & comprehend. Nice detail. You remind me of some of my voluminous COBOL programs, easy to follow in bite size pieces for who ever comes after me.

Maxwell
 

The King

Showercookie Monster
Sep 17, 2004
988
222
43
Denver, Colorado
#45
Quite well done. At MARS we figured out it was ALL about lock time in gas guns. You need to be a rock solid shooter in every way to get good gas gun performance.

Some gas guns had up to 10 times the lock time of an excellent bolt gun.



Rudy
Your explanation was so easy to follow & comprehend. Nice detail. You remind me of some of my voluminous COBOL programs, easy to follow in bite size pieces for who ever comes after me.

Maxwell
 
Nov 9, 2013
284
19
18
Missouri
#46
Another Seekins SP-10 6.5 owner here, mainly used as a LD hog whacker. Couldn't want for anything more. Have RRA LAR-8's in .308 & .243 that held up their end accuracy-wise, although RRA's proprietary approach to life is tiresome.
 
May 3, 2013
141
5
18
#47
I read a lot of nightmare stories from guys building their own 6.5 creedmoor gas guns. To make my build as smooth as possible I asked guys on here and jp precision themselves what to run. They recommend their JPSCS2-10h2 silent capture with h2 heavy buffer, JPBC-4 low mass bolt carrier and the barrel is their 22” with xl length gas tube. I chose jp because I have one of their ctr-02 ar15 rifles which shoots fantastic.
 
Likes: ChadL

ThatOneGuy2830

New Hide Member
Mar 10, 2018
6
14
3
#48
Another Seekins SP-10 6.5 owner, I mainly use it for target shooting. I have about 700 rounds through it and it is holding up well. Initially had to tweak the gas system. Rapid fire seems not to degrade accuracy at range either. My best groups have been a little under 3/4 MOA with factory match ammo. Occasionally when the rifle was new stovepipes were a issue, but after about 150 rounds or so that has not been an issue. I really enjoy the rifle and the price was hard to pass up compared to similar rifles.
 
Apr 10, 2017
293
22
18
Houston, Texas
#49
I want to thank the OP and the people who took the time to respond to this thread.
I am in the market for a 260 in a semi and this was great help in answering many of my questions.
Steve
 
Jan 9, 2018
5
0
1
#50
Are you actually recommending a rifle that you have not shot to any great degree?
No sir, just stating what I have and it comes with a smooth action, crisp trigger, and a HB. I have the factory test target of under 1'' MOA guarantee.
I do not live in a free state and relocated it with a relative. So I actually need more than a scope for it. I also need a different grip to be within the compliance of the legislation. I have yet to shoot a scoped rifle. I come here often to read and learn. I usually don't post. All in all I was just wanted to share the fondness I have for that rifle.
 
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