Barrett MRAD and multiple cartridges

Trying to wrap my head around the MRAD for .338 Lapua, 300 Win Mag, and .308 Win. Maybe .260 Rem.

The thing I am having a hard time with is using one scope for all those cartridges. Would using multiple scopes with quick detach scope rings be the way to go, with a specific scope set up for each cartridge, or would a single scope be able to work across all those cartridges?

I would just have a dedicated rifle for each cartridge/caliber. I already have a 338 and a 308. I'm thinking a 300WM in an AR platform.. Then each rifle has its own scope

fabsroman said:

Trying to wrap my head around the MRAD for .338 Lapua, 300 Win Mag, and .308 Win. Maybe .260 Rem.

The thing I am having a hard time with is using one scope for all those cartridges. Would using multiple scopes with quick detach scope rings be the way to go, with a specific scope set up for each cartridge, or would a single scope be able to work across all those cartridges?

Click to expand...

1) MRAD: Nothing more, or less, than a standard unit of angular measure, very much like the Minute of Angle. It is not associated with any particular cartridge, it is just a unit by which the scope is adjusted, and so a scope using mil adjustments can be used with any cartridge.

If one takes a circle and measures from the center to the edge, this is the radius. If one measures around the circle, this is the circumference.

If one then takes a section of the circle's circumference that is equal in length to the radius, that arc length and resulting angle forms a radian. If we divide that arc length by 1,000, we arrive at one one thousandth of a radian, which is a milradian. Milradian is the actual term.

This milradian, 1/1,000th of the radian (and radius), is used as a unit of angular measure and is sometimes called a "milrad", "mrad" or "mil". Because it is derived by dividing the radian by 1,000 and the radian arc length had been equal to the radius, one milradian is equal to 1/1,000 of the distance to the target.

At 1,000 yards, it is one yard. At 1,000 meters, it is one meter. At 1,000 miles it is one mile. At 1,000 inches, it is one inch. It is NOT metric, it is not imperial, it is a unit of angular measure based on the ratio of 1:1,000.

At 100 yards, a milradian is 3.6" (100 yards x 36" / 1,000). Scopes using the milradian system usually adjust in 1/10th mil clicks, so at 100 yards, one click is .36", just under 3/8". At 1,000 yards, one click is 3.6".


2) MOA: A Minute of Angle is also a standard unit of angular measure and is called "Minute" or an "M.O.A.". It is NOT a Moa (mow`ah), which is a very large extinct, flightless, carnivorous bird having nothing to do with geometry.

If we divide a circle's circumference by 360, we arrive at one degree. If we then divide this degree into 60 sections, we will have one minute of angle.

The arc length of one minute of angle is 1.047" at 100 yards. At 1,000 yards, one minute of angle is 10.47" and a reasonable approximation is to think of it as one inch per hundred yards (6" at 600, 8" as 800, etc..).

Scopes using the MOA system of adjustment usually use 1/4 MOA clicks, so at 100 yards, one click is 2.6" (1.047" / 4 = .26175"). At 1,000 yards, one click is 2.6".

If a milradian based scope adjusts 3.6" per click at 1,000 yards and the minute of angle based scope adjusts 2.6" per click at 1,000 yards, it is obvious that there is almost no difference in the values provided by each system. 1" at 1,000 yards is invisible to the average shooter. One system is no better than the other.


3) Trajectory compensation: Both systems, milradian and minute of angle, simply provide incremental adjustments to offset drop and wind and can be applied to any cartridge.

If you are around 10" low at 1,000 yards, you can either dial up 1 moa (four clicks of your MOA based scope) or you can dial up .3 mils ( three clicks on your Mil based scope.

The four cartridges you list will all have differing trajectories, in that they will each drop a different amount at any given distance, and thus each will require a different amount of compensation.

Trajectories will not only vary cartridge to cartridge, but will also vary rifle to rifle and with atmospheric conditions, so we will move forward with generalities from this point.

From a 100 yard zero:

The average .338 Lapua 300 grain load will drop about 269" by the time it gets to 1,000 yards. You would dial up about 7.6 mils from your 100 yard zero with a mil based scope, or you would dial up about 25.75 minutes of angle on your MOA based scope. Both units of measure describe the same drop amount and both adjustments can put you on target.

The average .300 WinMag 190 match load will drop about 276" at 1,000 yards, so we would dial up about 7.8 mils or about 26.5 MOA. Both units move the bullet the same amount.

This might be a good time to note that there is VERY little difference between the .338 LM and .300 WM as close as 1,000 yards (even with the rather lame 190 in the .300) and if you never shoot past that, the .338 doesn't buy much. If you handload (to reduce SD) and can get past 1,500 yards, the .338 begins to show a substantial advantage.

The average .308 175 match load will drop about 399" at 1,000 yards, so we will adjust our scopes by 11.3 mils or by 38 minutes respectively.

The average .260 Rem 140 match bullet drops about 288" at 1,000, so we'd dial to an approximate value of either 8.1 mils or 27.5 MOA to correct this drop.

As can be seen, the same scope(s) will work for any cartridge and we simply have to adjust for that particular cartridge's drop characteristics and the current environmental conditions.


4) Scope utilization: I HATE swapping scopes around. It requires a zero session every time it is moved, no matter whose mounts you use. Using those throw lever, quick detachable mounts (meant for carbines at carbine ranges) undermines the integrity of the entire system and WILL eventually loosen up, and further, the rail specs and tolerances are such that it is extremely unlikely the throw levers can simply be moved from rifle to rifle without adjusting the tension.

There can also be issues with optimum height and clearances, so if all the rifles that may use a certain scope are not the same, some matches will not be good. Either the scope is too low and touches something or it is too high and you will break position or have to pad up the cheekpiece to get behind it.

I do understand that good scopes are expensive and one cannot always justify putting a dedicated scope on each rifle, but I would personally stop buying rifles I couldn't afford to outfit properly before I stopped buying scopes to mate with them. When I get a rifle, I will put the appropriate scope on it with the most appropriate mounts for best fit, torque it all down, tightly install a sunshade and put lens caps on and it will stay that way.

That said... Yes, the same scope can be used on multiple rifles, regardless of the system of angular measure used. Were I forced to do this, I would use standard Picatinny rings with crossbolt type connections to the rifle rail and wouldn't use a set of throw lever rings on a real rifle if someone gave them to me for free.

Each rifle will have a separate ballistic path and once the 100 yard zero is arrived at or returned to, you will consult your range card to ballistic software for the approximate correction for any given range and environmental condition.

To run the scope on different rifles and cartidges/loads you'll need a little booklet with base setting for each rifle and each caliber and each load and same mount/rails. The info will get muddled if not written down. You'll need the external ballistcs anyway but it is the the base setting on each rifle which are the issue. Shooting 4 guns in Hunters Pistol with dedicated sights/scopes and unique base settings using two different loads in two guns can be mentally cumbersome and without a booklet errors could ensue. Then are all those picatinny rails exactly the same to .001"? I'd go with one scope for each rifle or upper.

Now a rifle with quick change barrels and calibers...same issues but the scope stays in one place.

Nice post, E. Shell...as usual.

So I'd have to count 76 clicks on a milrad scope for 7.6 mils. Uh, I can barely count to 20 without losing count.

Are there adjustments on milrad scopes that give tactile feedback at, say, every 10 clicks? Or does one simply have to keep track either tacitly or visually?

whistlersmother said:

So I'd have to count 76 clicks on a milrad scope for 7.6 mils. Uh, I can barely count to 20 without losing count.

Are there adjustments on milrad scopes that give tactile feedback at, say, every 10 clicks? Or does one simply have to keep track either tacitly or visually?

Click to expand...

All have tactile clicks so you can see/feel the exact position of the turret, but you do not count clicks, no more than you'd count eights to find one inch on a ruler.

No one counts clicks, there is no need to. Scope turrets are marked like a ruler and you read the value exactly like you would a ruler. You'd dial right up to the number 7, then go one click past halfway to 8.

one scope, something like nightforce 5.5-22x56 will handle all of those calibers, distance-wise. but it's going to be a PITA to re-zero or adjust between each caliber switch. it's tempting to have one gun/chassis and one scope for multiple uses (saves a LOT of money) but quickly becomes a pain to switch everything around.

maybe just start off with 300wm and see if that will fit all your uses.

E. Shell,
Thanks for the info. and the lesson. I think you just put 1000 pages of instruction in a couple of paragraphs. I love reading condensed versions. My ADD kicks in after a couple of pages of any kind of reference info. Even something I'm interested in.

davsco said:

one scope, something like nightforce 5.5-22x56 will handle all of those calibers, distance-wise. but it's going to be a PITA to re-zero or adjust between each caliber switch. it's tempting to have one gun/chassis and one scope for multiple uses (saves a LOT of money) but quickly becomes a pain to switch everything around.

maybe just start off with 300wm and see if that will fit all your uses.

Click to expand...

I already have a Ruger 77MKII in .300 Win mag that I use for hunting. Was thinking about getting the Barrett MRAD in .338 Lapua. The ability to shoot other cartridges out of it is alluring, but dealing with the scope is a PITA. I've never used quick detach scope mounts on a rifle. Getting ready to buy some for an AR that I am going to use an Aimpoint red dot on. Not too worried about it keeping exact zero since it would most likely be used for 100 yards or less. However, how reliable are quick detach scope mounts for something that is going to be used around 500 to 1,000 yards?

I wouldn't mind buying a separate scope for each and every cartridge, if need be, and then using quick detach mounts on all of them.

Then, I wonder if there are any digital scopes out there that would work for multiple cartridges without having to change out the scope. Two come to mind off the top of my head:

http://www.burrisoptics.com/scopes/...pe-series/eliminator-iii-laserscope-4-16x50mm

https://www.atncorp.com/x-sight2-hd...RtbLIk2F7vxDacpbCVYzXaqd1SfWXWbbYIaAmCR8P8HAQ

just fyi at the fnh 3 gun match a few years ago they had a MRAD in 338LM as a prop gun, with a b/c plate out at 500 yds. pretty much everyone got a first shot hit, not that that is any extreme distance. they also let me have some fun with it after the match. with its weight, rear bag and shooting prone, pretty much no felt recoil.

any idea what the MRAD accuracy (POI) is when switching barrels back and forth? is it 100% repeatable?

davsco said:

just fyi at the fnh 3 gun match a few years ago they had a MRAD in 338LM as a prop gun, with a b/c plate out at 500 yds. pretty much everyone got a first shot hit, not that that is any extreme distance. they also let me have some fun with it after the match. with its weight, rear bag and shooting prone, pretty much no felt recoil.

any idea what the MRAD accuracy (POI) is when switching barrels back and forth? is it 100% repeatable?

Click to expand...

That is something that I am going to have to figure out. Does it make sense to buy a rifle with barrels that can be changed. The Sako TRG-M10 has barrels that can be changed, and I was seriously contemplating it, but I believe it only has 308 Win and 338 Lapua as options.

Barrett, Sako, Barret, Sako. Right now, I am leaning towards the Barrett, but I have to do a lot more research before dropping $6k on a rifle. This might not even be the best chart board to get opinions on the Barrett MRAD.

With that said, thanks for your opinion on how it shoots out to 500 and the felt recoil, or lack thereof, in 338 Lapua.

while we have some excellent resources here, and i'm def not including myself, also go check out brianenos.com. they have a long range subforum. also snipershide.

davsco said:

while we have some excellent resources here, and i'm def not including myself, also go check out brianenos.com. they have a long range subforum. also snipershide.

Click to expand...

Thanks. Already knew about snipershide, but had never heard of brianenos. I'll bookmark brianenos and check both of them out as I do my research.

fabsroman said:

That is something that I am going to have to figure out. Does it make sense to buy a rifle with barrels that can be changed. The Sako TRG-M10 has barrels that can be changed, and I was seriously contemplating it, but I believe it only has 308 Win and 338 Lapua as options.

Barrett, Sako, Barret, Sako. Right now, I am leaning towards the Barrett, but I have to do a lot more research before dropping $6k on a rifle. This might not even be the best chart board to get opinions on the Barrett MRAD.

With that said, thanks for your opinion on how it shoots out to 500 and the felt recoil, or lack thereof, in 338 Lapua.

Click to expand...

All this talk and no AI AXMC?

Anywho. Regardless of what you end up with, all you need to do is zero the rifle once. Then swap the barrel and shoot a sighter group; this group will be offset by a certain amount from your original zero, write those values down and do not change your scope zero. Rinse and repeat with each barrel or load. Save zero-offset values in your favorite ballistic program.

For instance, I have my rifle zeroed with 130gr PRIME, but I shoot it suppressed from time to time. In my ballistic app on my phone I have two profiles saved for this ammunition for either of the two aforementioned situations. Data between the two is identical save for zero-offset value; Suppressed profile has offset of -2.25" indicating it shoots 2.25" low at 100yd versus my scope zero. I have two more profiles for Hornady 140gr ELD-M for both with and without suppressor: ELD-M is .25" low, ELD-M suppressed is 2.5" low compared to my zero (which again, is for 130gr unsuppressed). One scope, one gun, multiple zeroes, all stored on the phone.

OrbitalEllipses said:

All this talk and no AI AXMC?

Anywho. Regardless of what you end up with, all you need to do is zero the rifle once. Then swap the barrel and shoot a sighter group; this group will be offset by a certain amount from your original zero, write those values down and do not change your scope zero. Rinse and repeat with each barrel or load. Save zero-offset values in your favorite ballistic program.

For instance, I have my rifle zeroed with 130gr PRIME, but I shoot it suppressed from time to time. In my ballistic app on my phone I have two profiles saved for this ammunition for either of the two aforementioned situations. Data between the two is identical save for zero-offset value; Suppressed profile has offset of -2.25" indicating it shoots 2.25" low at 100yd versus my scope zero. I have two more profiles for Hornady 140gr ELD-M for both with and without suppressor: ELD-M is .25" low, ELD-M suppressed is 2.5" low compared to my zero (which again, is for 130gr unsuppressed). One scope, one gun, multiple zeroes, all stored on the phone.

Click to expand...

Well, that throws one more rifle into the running. Looks like the Accuracy International rifle is offered in .338 Lapua, .300 Win Mag, and .308 Win just like the Sako. Think the .260 Rem has me leaning toward the Barrett.

Edit to add: I will have to look into the smart phone app. Good thing I have a smart phone for this. lol

fabsroman said:

Well, that throws one more rifle into the running. Looks like the Accuracy International rifle is offered in .338 Lapua, .300 Win Mag, and .308 Win just like the Sako. Think the .260 Rem has me leaning toward the Barrett.

Edit to add: I will have to look into the smart phone app. Good thing I have a smart phone for this. lol

Click to expand...

AI is a bit confusing...there's the real AXMC (the long action) and then the AX308 (short action) which occasionally referred to as the AXMC308. The short action gun is cheaper and CAN NOT be converted to long action calibers, so you need to make sure you're looking at the .338LM or .300WM base rifle plus the cost of .308 bolt, short action mag, magwell adapter, and new barrel. Last time I looked a .308 conversion kit added a pretty significant cost to the long action rifle, but you can buy it piecemeal and get your own .260 barrel over the AI .308 barrel in the kit.

That said, if you can live with a short action which isn't the point of this thread at all, AI does offer factory short action rifles in .260 Rem.

fabsroman said:

That is something that I am going to have to figure out. Does it make sense to buy a rifle with barrels that can be changed. The Sako TRG-M10 has barrels that can be changed, and I was seriously contemplating it, but I believe it only has 308 Win and 338 Lapua as options.

Barrett, Sako, Barret, Sako. Right now, I am leaning towards the Barrett, but I have to do a lot more research before dropping $6k on a rifle. This might not even be the best chart board to get opinions on the Barrett MRAD.

With that said, thanks for your opinion on how it shoots out to 500 and the felt recoil, or lack thereof, in 338 Lapua.

Click to expand...

Sako M10 also does .330 WM.

But it is $10K. IIRC, that is for one caliber.

Or buy one TRG-22 (.308) and two TRG-42s (.300 WM and .338 Lapua) for a total of about $9K.

Plus optics.

I was thinking of building a .300 WM to match my 700 based .308 long range rifle. But it will cost almost as much as a TRG-42 in .300 WM. I asked over on Sniper's Hide, and OVERWHELMINGLY, the advice was to buy the Sako and not look back.

Pinecone said:

Sako M10 also does .330 WM.

But it is $10K. IIRC, that is for one caliber.

Or buy one TRG-22 (.308) and two TRG-42s (.300 WM and .338 Lapua) for a total of about $9K.

Plus optics.

I was thinking of building a .300 WM to match my 700 based .308 long range rifle. But it will cost almost as much as a TRG-42 in .300 WM. I asked over on Sniper's Hide, and OVERWHELMINGLY, the advice was to buy the Sako and not look back.

Click to expand...

Thanks Pinecone. I had been thinking about building up a Rem 700 type action on a Borden receiver, but then I thought better about it. Just so many guns out there that are better than a Remington 700 action. Sako, Barrett, McMillan.......

I am going to have to think about this some more. Initially, I was going to go with the Sako TRG-42 in .338 Lapua, but then saw the M-10. Thing is, when will I really need to swap cartridges on the gun? I already have a Ruger 77MKII in .300 Win Mag. Granted, not in the same class as a Sako TRG-42 in .300 Win Mag, but if I already have a Sako TRG-42 in .338 Lapua, do I really "need" another Sako TRG-42 in .308 Win, .300 Win Mag, etc.?

Yep, going to have to do some more pondering on this before I "pull the trigger", literally and figuratively.

maybe the 338LM that will do anything and everything, and an ar-10-based gas gun in 308 or 6.5cm if you want a little quicker action, less recoil, cheaper shooting but still LR accurate (JP, Les Baer, Wilson, GAP).

davsco said:

maybe the 338LM that will do anything and everything, and an ar-10-based gas gun in 308 or 6.5cm if you want a little quicker action, less recoil, cheaper shooting but still LR accurate (JP, Les Baer, Wilson, GAP).

Click to expand...

Yeah, already have 3 AR-308 lowers to finish building up.

Then, getting a Ruger .308 bolt gun might be the right way to go. Either the 77 Hawkeye Target in .308 Win or the Ruger Precision Rifle in .308 Win. I'll probably go with the latter. Starting to come back to the Sako TRG-42 in .338 LM with a dedicated scope for it. The thought of barrel swapping and dealing with the scope(s) is giving me a bigger headache than I already have.