Ridgeline Defense RD-15 LPR
- Thread starter B4forever
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1.) There is a 11.5/12.5 CQBR (basically a compact LPR) on the drawing board currently. Not sure which length just yet but I do have some prototype 11.5 barrels from the RDM4 project that have shown some great results.
2.) Regarding the difference in design, I’d wager it’s fairly similar from big picture perspective. The semi-monolithic rail concept isn’t exactly something we pioneered it’s just that it didn’t seemed to be being paired with some of the other concepts we wanted to see as shooters.
The big difference I will point out is the effort that we put into pair and fitting upper receivers, barrels and gas systems. We could batch test parts and simply pay somebody minimum wage to assemble and ship rifles, and I’d suspect a good chunk of the rifles would be fine, kinda like grandmas old fashion fried donuts, it’s just a good recipe. Problem being though is that for certain end users, especially in a professional capacity, your time should not/cannot be spent troubleshooting or second guessing a rifle out of the box. You’d be surprised how many little things that get caught during 100% CQ that are showstoppers for producing functional rifles.
That said we currently have something like a 98% first-time pass rate for during accuracy/function testing. Turns out even when following the recipe, it’s still not a perfect thing. “Trust…but verify” is the name of the game. There are certain aspects of a rifle that just can’t be measured outside of live fire.
And that’s the difference between us and the others. Most companies in this industry have a “guarantee”, The guarantee that most companies have nowadays is a just a promise that it should be good and if it doesn’t buff just send it back. This is the cheapest way to deal with performance issues because in reality most of the time it is probably good …and/or they are banking on you not being able to tell the difference. The requirement on the other hand is what we’re offering with every LPR. We are not just promising you it will perform, we are showing you that it did in fact perform to at or above the standard we promise. This is the single biggest difference I see.
@Rudy Gonsior
1. I appreciate the response. Looking forward to a hopeful 12.5 upper! Makes me consider holding off building one for now. Big fan of that barrel length and 77SMK class bullets. Its just so well rounded giving up only 50-75 yards of comprable data to a 16" barrel.
2. Thats what I figured. RDs QC seems like it goes to the "nth" degree and makes the upper stand apart.
Thanks again!
1. I appreciate the response. Looking forward to a hopeful 12.5 upper! Makes me consider holding off building one for now. Big fan of that barrel length and 77SMK class bullets. Its just so well rounded giving up only 50-75 yards of comprable data to a 16" barrel.
2. Thats what I figured. RDs QC seems like it goes to the "nth" degree and makes the upper stand apart.
Thanks again!
That’s great news. Any thoughts on if 6 ARC will be offered? Or a 14.5” 556 LPR that can be updated with a new bolt and 14.5 proof barrel on my end?
If (big if here) a 6 ARC can be made to an acceptable MRBS/F then maybe within the year but it’s a tall order.
A 14.5 (Proof barrel) LPR is drawn up but it’s back burner project. I suppose you could cut a 16” LPR if you’re feeling crafty. I wouldn’t go changing the bolt though.
Nope, I am just smoking crackCut a 16” back
Maybe I missed it, but mid-length gas, intermediate or a custom length of your own ? Thinking mid-length with the A5 system unless you have a special weight buffer??
@Rudy Gonsior
Can you talk any about the "barrels" under parts and accessories that are coming soon?
Can you talk any about the "barrels" under parts and accessories that are coming soon?
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I filmed it already but I blacked out, so not 100% sure but I think that’s what is next though.
Big fan! Always appreciate your classes as a NH resident.
Curious what your reference to swapping the bolts? Are you finding that truly matching headspace to the barrel extensions has a material improvement on accuracy? Versus the generally accepted attitude that all AR15 bolts are interchangeable with barrels?
So, are the AR10 type still gonna be named "Murder Sticks"? 
Just picked up my RD-15 LPR today, and wanted to ask those who also have them about the fit between the upper/lower.
I've heard a lot of people rave about how tight the fit is between the receivers, but mine has a good amount of slop. I compared it to my Radian, and I couldn't get that upper to budge at all it's so tightly fit. However with the RD-15 I'm able to jiggle the upper just using my thumb and forefinger without much effort. It has about the same amount of slop as an Aero upper/lower I have.
Is this expected? I'm not as familiar with AR's as I am with bolt guns, so maybe I'm slightly biased in being used to everything being very tight fitting, but I'm really surprised by the difference in the amount of play coming from the Radian vs the RD-15.
I've shot Ridgeline an email to ask them the same question, but just wanted to see if others have the same thing, and it's normal, or if mine is an anomaly.
I've heard a lot of people rave about how tight the fit is between the receivers, but mine has a good amount of slop. I compared it to my Radian, and I couldn't get that upper to budge at all it's so tightly fit. However with the RD-15 I'm able to jiggle the upper just using my thumb and forefinger without much effort. It has about the same amount of slop as an Aero upper/lower I have.
Is this expected? I'm not as familiar with AR's as I am with bolt guns, so maybe I'm slightly biased in being used to everything being very tight fitting, but I'm really surprised by the difference in the amount of play coming from the Radian vs the RD-15.
I've shot Ridgeline an email to ask them the same question, but just wanted to see if others have the same thing, and it's normal, or if mine is an anomaly.
Mine isn’t sloppy but it isnt super tight. My radian is way tighter, especially with the tension adjustment.
Thanks for reaching out, I look forward to catching the email and getting some more details. Typically anytime there is an issue we'll conduct a RMA to try and nail down exactly what's happing.
While I wait, I think the best way to answer what I can is to walk through the LPR specs which I think is a little misunderstood. And just to be clear it's possible the receivers in this particular case could be out of spec, I don't think it would be unlikely...but again I can't say for sure without looking at it so everything that follows is just for better understanding in the interim.
So first of all, regarding the upper to lower fitment, let me say this has no impact on the mechanical accuracy. I feel like this gets argued a lot across the internet but in fact some of the best shooting LPRs cataloged in testing to date are "lose" arrangements.
We do however understand that the "feel" of a tight fit is physiologically boosting, I remember having a wobbly A2 back in the day and it wasn't confidence inspiring. Thus, we specifically hold our lug/recess tolerances on the LPR to what is conceivably practical. As an example the M16 TDP (technical data package) which is the standard industry specifications for forged receivers (note there are some slight variations to this over the years but this was the tightest listed dimensions I've seen listed), the maximum thickness of the lugs is 0.499" and a minimum of 0.496 while the recess has a tolerance minimum of 0.500 and maximum of 0.504 meaning traditional you'll have anywhere from +0.001 to +0.008 gap fitment between receivers. Again, this is the tightest of the official revisions I've seen personally, it only gets loser from there.
The RD15 departs from the TDP spec in that our lugs/recess are held to have anywhere from +0.000 to +0.003 gap fitment between receivers. This drastic improves the fit and feel of the rifle for the end user but still allows for realistic production rates. The reality is you could attempt to tighten tolerances but between machining and anodizing you would probably only be able to realistically narrow the gap to 0.002". And of course, doing so would drastically up your rejection rate, material loss and machine time per unit, never mind the fact that you wouldn't have too many friends in the machine shop. Last but not least the cross-compatibility aspect of the LPR of folks wanting to put uppers on lowers would become even more problematic.
This of course means some rifles inviably fall into the 0.003 gap range and will have some minor play. This is why you see a lot of companies introducing tensioning screws and such things into their designs. Personally, I think there is a line of dimensioning returns somewhere close by as again the actual effect on performance isn't. I suppose an inline revision is feasible should the need be presented but hope this gives a little more clarity and context to the dimensional relationship of the LPR‘s lug and receiver interface.
Thanks for the reply Rudy. I trust you guys know what you're doing, and that I am being overly cautious (again, I'm a little newer to AR's than bolt guns). I did get the RMA and have shipped it back to you. I apologized to Blake in advance if there is nothing wrong, but I'm grateful for the customer service of being willing to take a look.
The purpose behind the Mil-Std TDP for M16s/M4s is “replaceability" by field-level armorers and repair vehicles or facilities.
Say a truckload of soldiers gets hit with submunitions or a bomb and it blows everyone and everything to hell.
During the battlefield recovery efforts, all equipment and weapons salvaged will be processed through a system, so if some barrels are bent or other parts unserviceable, armorers can check the remaining parts that are not damaged or unserviceable, and mate them to other serviceable parts to form complete weapons.
The AR-15 family of weapons beat all the other designs in this respect, including the highly-modular Hk G3/Hk33/MP5 weapons.
In the civilian market, precision shooters and upper-tier customers tend to desire that vault-like fit/feel/function of a wedged rear lug and .001” lowered TD pin hole receiver set.
Anodizing thickness variations will play around with this even when you do set an in-house standard, then it walks away from you in processes even when the machining is dead-nuts on.
I’ve had this conversation with several other major manufacturers in the AR-15 world specifically, and it’s all about processes and tight controls if you want to produce consistent product like that. Very hard to do if you’re not an A-hole to the different people in their respective manufacturing spaces who supply or work for you.
Say a truckload of soldiers gets hit with submunitions or a bomb and it blows everyone and everything to hell.
During the battlefield recovery efforts, all equipment and weapons salvaged will be processed through a system, so if some barrels are bent or other parts unserviceable, armorers can check the remaining parts that are not damaged or unserviceable, and mate them to other serviceable parts to form complete weapons.
The AR-15 family of weapons beat all the other designs in this respect, including the highly-modular Hk G3/Hk33/MP5 weapons.
In the civilian market, precision shooters and upper-tier customers tend to desire that vault-like fit/feel/function of a wedged rear lug and .001” lowered TD pin hole receiver set.
Anodizing thickness variations will play around with this even when you do set an in-house standard, then it walks away from you in processes even when the machining is dead-nuts on.
I’ve had this conversation with several other major manufacturers in the AR-15 world specifically, and it’s all about processes and tight controls if you want to produce consistent product like that. Very hard to do if you’re not an A-hole to the different people in their respective manufacturing spaces who supply or work for you.
@Rudy Gonsior
Are any of you guys reloading for these rifles? I recall Jay saying in a class that 23.8gr of 8208 + 77SMK worked magic, which is where my load settled for a Mk12. Curious if you guys have done any load development for the rifles. I have an upper inbound due tomorrow.
Are any of you guys reloading for these rifles? I recall Jay saying in a class that 23.8gr of 8208 + 77SMK worked magic, which is where my load settled for a Mk12. Curious if you guys have done any load development for the rifles. I have an upper inbound due tomorrow.
I don't have one of these rifles, but I've loaded a ton of 77 SMK'S using IMR 8202 XBR. I've settled on 23.5 grains which is well under 1 MOA in my primary AR and no worse than 1.25 in anything I've ever tried, it also gives just under MK262 velocity. 23.8 sounds a little spicy, you can do it, but it's really pushing brass life.
Yeah it's totally up to the rifle. It was definitely hot in another 16" mid gas gun but has had a bit of primer flattening and that's it in a Mod1. It was also fine in a Douglas 16" SPR Barrel, but then another Douglas had it a bit warm.
My guess is somewhere in the 23.2-23.8gr range.
Naw I don’t hand load for .223/5.56 these days as it’s just not worth the effort. Factory ammo is pretty good and my time is worth more than any theoretical savings I might gain sitting behind a reloading bench. But a 77smk sitting over 23.8 of 8208 is a classic load mimic of Mk262 though and I’ve had success long ago in that range. As always work your way up responsibility.
As factory ammo goes obviously FGMM is king of accuracy but is a little slow for some peoples taste. But the Black Arc NAS3 Mk262 “Alpha” has been absolute fire for field work though. Routinely clocking 2780’s out of 3 different LPRs with SD of 5 to 7.
For those looking for a better price point the AAC 77 SMK load has been a pretty fair loading in the LPR according to the guys up North. I can’t recall the accuracy or velocities they mentioned but I remember them remarking it being in the range of “decent for the price”.
Rudy, I wasn’t closely following so I’ll just ask - did the standalone uppers receive a slight price break as well? The results speak for themselves for anyone wanting a proven system and not piecing together all the parts themselves. Thank you
I honestly don’t know but looking at the website it shows it listed at “$1799” which is the same price originally I think. I’ll ask someone who knows.
And for those curious about stand alone uppers in FDE, yes they are coming at some point but every that is FDE is going to rifles at the moment.
Thanks for checking on that! I saw the price drop in snagged an upper this week. Anyway. Curious how this works out. Local to New Hampshire so it's arriving this afternoon.
Sounds good. I'm sure it will shoot or they will take care of it. Wife is due any day so it may be a few days. If it gets here tomorrow I will.try to shoot some groups with the loads I have.
I wouldn't be surprised if the uppers don't come with test targets, but they should still shoot well.
My upper did not come with a test target but does shoot handloaded 77SMKs at 2780 in a consistent 0.5moa 5 round group. IMI 77gr at 0.75 so it does shoot.
Holy crap that is really, really hot and fast out of a 16". What are you running for a load?
Did it take a while for the proof barrel to speed up and settle in?
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All LPR uppers are made on the same assembly benches, to the same standards. The standalone uppers get pulled prior testing as there are simply to many variables with components outside of our control to bother with, them being standalone sub-assemblies.
99% of the time it should be fine but we definitely stand behind our concept so even in that 1% scenario we’ll do our best to help you out.
Obligatory warning I am just another idiot online who may reload while drinking so take the load for what its worth.
LC Mil Brass
CCI 41
25.8gr Ramshot Tac
77 smk
2.300 COAL (Yes still feeds out of mags)
QL has it at about 65000psi
Barrel took about 200rds to really settle in.
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How does the brass look?
Did the barrel shoot accurately out of the gate and just keep speeding up?
How is the temp sensitivity on Tac?
Brass looks fine but in my experience .223 doesn't show pressure signs until it does... So while I've had success loading .223 hot I try not to push the upper upper limits. Extra COAL helps a bit keeping pressure down.
Barrel shot well out of the gate, groups maybe tightened slightly but it was the speeding up I was watching for. The 200rd mark was more a cautionary move on my part less a hard number. Hell you may be good after 20 rounds.
Temp sensitivity sucks with Tac, like any ball powder
Yeah that's been my experience with the temp stuff. In NH it can be 95' in the summer and 0' in the winter, and I'm too lazy to have different loads for different seasons. My mk12 mod 1 runs about 2750 with 8208 so I figured this should run mid 2600s which is more than fine.
Agreed and would do the same. 8208 has been tough to find, great powder though. That 25.8gr load was the top end of my load development but seemed to shoot fine. Was pleasantly surprised at the lack of gas in the face and still proper ejection so they did a good job gassing the rifle even with a can on there.
I stocked up on like 10lbs of it over the summer when it hit stock again. Should last me a few thousand rounds.
May try StaBall again too, we will see.
Upper is in and I am really digging it!
The fit with my PRI lower is tight. I mean right. Zero wobble.
It is the softest shooting AR I have ever fired. I ran it with an RC2 and closed time flash hider (waiting on an RC3 and 3 prong). It is as soft, if not softer, than my Mk12 Mod 1 with an OCM5 and BRT reduced gas tube.
I ran my 77 Nosler handloads through (23.8gr 8208 in LC brass with CCI Small Rifle primers). No pressure signs.
The paper was pretty shot up, but I shot several 10 round groups from prone with a bag with each group shot in under 10 seconds. It's a clear shooter. Both groups were 1" with one that would have been 3/4" of I hadn't dropped a round now. That's fantastic for 10 round groups.
The handloads get 2750fps out of the 18" Mk12 Mod 1 Douglas barrel and 2650 of of another 16" Douglas barrel. I chronoed 14 rounds after shooting 50 rounds and got a 2570fps average with an SD of 23. I am hopeful it will speed up and settle in 300-400 rounds. Time to burn some blasting ammo.
I am super happy with it so far.
The fit with my PRI lower is tight. I mean right. Zero wobble.
It is the softest shooting AR I have ever fired. I ran it with an RC2 and closed time flash hider (waiting on an RC3 and 3 prong). It is as soft, if not softer, than my Mk12 Mod 1 with an OCM5 and BRT reduced gas tube.
I ran my 77 Nosler handloads through (23.8gr 8208 in LC brass with CCI Small Rifle primers). No pressure signs.
The paper was pretty shot up, but I shot several 10 round groups from prone with a bag with each group shot in under 10 seconds. It's a clear shooter. Both groups were 1" with one that would have been 3/4" of I hadn't dropped a round now. That's fantastic for 10 round groups.
The handloads get 2750fps out of the 18" Mk12 Mod 1 Douglas barrel and 2650 of of another 16" Douglas barrel. I chronoed 14 rounds after shooting 50 rounds and got a 2570fps average with an SD of 23. I am hopeful it will speed up and settle in 300-400 rounds. Time to burn some blasting ammo.
I am super happy with it so far.
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Round count is now around 100 with the 77gr 8208 handloads plus another 100 of 55gr blasting ammo.
The barrel has not sped up much, however the SD did really start to settle down. This isn't a load I developed for the rifle as I really like to run the same 77gr 5.56 loads through all of my rifles. It shoots 1MOA or slightly better with 10 shot groups and is now producing a velocity of 2582fps with an SD of 16. I will recheck this again in another 200+ rounds.
One thing that caught my eye is that the rifling is the lands within the barrel are frankly just rough. I compared it to the Douglas barrels I have (16" and 18") and both are just a lot smoother. Borescopes aren't the be-all-end-all, but I do wonder if that is why this barrel just seems a bit slow. If I can get it to low 2600fps I would be very happy. My 16" Douglas with the same loads is about 2650fps.
Of note, the gas port was not drilled in the groove completely, however neither of the 2 PRI Douglas barrels did that either (the Mk12 Mod1 barrel I think is a 6 groove vs the 5 groove in the Proof). I am hoping that I don't get any weird erosion that could cause issues in the jacket of the bullet.
The barrel has not sped up much, however the SD did really start to settle down. This isn't a load I developed for the rifle as I really like to run the same 77gr 5.56 loads through all of my rifles. It shoots 1MOA or slightly better with 10 shot groups and is now producing a velocity of 2582fps with an SD of 16. I will recheck this again in another 200+ rounds.
One thing that caught my eye is that the rifling is the lands within the barrel are frankly just rough. I compared it to the Douglas barrels I have (16" and 18") and both are just a lot smoother. Borescopes aren't the be-all-end-all, but I do wonder if that is why this barrel just seems a bit slow. If I can get it to low 2600fps I would be very happy. My 16" Douglas with the same loads is about 2650fps.
Of note, the gas port was not drilled in the groove completely, however neither of the 2 PRI Douglas barrels did that either (the Mk12 Mod1 barrel I think is a 6 groove vs the 5 groove in the Proof). I am hoping that I don't get any weird erosion that could cause issues in the jacket of the bullet.
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You may want to look again, the gas port is in a land. Looks like it's splitting a Land and groove 50/50
Good catch! Updated to correct i! I doubt it will be an issue. It's definitely shooting well enough for what I would expect.
My RC3 is on its way to the dealer so I am really looking forward to seeing how this feels with that suppressor vs the RC2.
It does not, that is the top end of an 8208 charge. it should be getting around 2650fps once it settles. It is definitely slow right now. Several online videos said their barrel sped up by 100fps around 400 rounds in.
My previous barrel appeared to speed up around the 500 round mark. Hopefully yours does as well.
Black River Tactical chrome lined. I am at 238 on my current barrel (12.5" AR Performance) and have not seen any velocity increase. I expect to see it around 4-500, maybe less.
