Duplicating the MK316 Mod 0 QL request Please.

longrangehunter · Apr 5, 2019

I looking to duplicate the MK316 Mod 0 long range load AKA FGMM 308 175 SMK load. Only I'm using New Lapua brass vs the Federal FC or FGMM brass.

I am using the F210M primer, IMR 4064 powder, and the 175 Sierra MK #2275, all loaded to 2.8550" COAL which was .015" off the lands. The gun prefered .020" off BTW w/this bullet.

Here's the velocity at 20' from the muzzle. Barrel allowed to cool after every three shots. 24" BBL.

41.0 - 2545; 2578; 2548 all shot 20' feet from the muzzle (add 20 fps for actual muzzle speed).

41.3 - 2572
41.6 - 2575
41.9 - 2615

42.8 - 2658
43.1 - 2686
43.4 - 2714
43.7 - 2709

I see a node at 41.3-41.6, and 43.4-43.7, so what does QL show for B-times for OBT in a 24" bbl?

Thanks,

Dwh7271 · Apr 5, 2019

I’ll run you one when I get home.
I know that on the 175 gr Federal GM that 43 gr of RL15 pretty much duplicates it and even though the manufacturers use canister powder when you pull a 175 the powder looks an awful lot like RL15. :grin:

longrangehunter · Apr 6, 2019

Thanks!

I used that same data in my Kimber Advanced Tactical Rifle too, very accurate in that rifle! But I read years ago it was IMR 4064 in the MK316 Mod 0 vs the M118 LR, due to better temp stability over RL15. I just never got around to testing IMR 4064 in that rifle. So for I've used RL15, H4350, and IMR 4064.

Here's photo copy of the data sheet from Federal for this load: https://images.app.goo.gl/hRbE8LLJBs3ZcbmFA

My rifle doesn't shoot that bullet as well at the factory coal of 2.800"-2.8100", even with 41.6 grains of IMR 4064 as it does .020" which is 2.8500" coal. 2,600 fps is a little slow too! I went up to max velocity Hodgdon has listed in their manual with the 175 SMK and IMR 4064......... what was interesting is they list a max of 45.6 grains/2,728 fps! That's a case full of IMR4064 that's for sure, and compressed seated even long!

Dwh7271 · Apr 6, 2019

This should be pretty close.
See if this will work for you.

Code:

Cartridge          : .308 Win. (SAAMI)
Bullet             : .308, 175, Sierra HPBT MatchK 2275
Useable Case Capaci: 48.846 grain H2O = 3.171 cm³
Cartridge O.A.L. L6: 2.855 inch = 72.52 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : IMR 4064 ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-10.0   87    37.17   2344    2134   39138   6369     96.9    1.410
-09.0   88    37.58   2367    2177   40290   6434     97.2    1.391
-08.0   89    38.00   2390    2219   41475   6498     97.5    1.373
-07.0   90    38.41   2413    2262   42694   6560     97.8    1.355
-06.0   91    38.82   2436    2306   43947   6620     98.1    1.337
-05.0   92    39.24   2459    2350   45236   6678     98.3    1.320
-04.0   93    39.65   2482    2394   46562   6735     98.5    1.303
-03.0   94    40.06   2505    2438   47925   6789     98.7    1.286
-02.0   95    40.47   2527    2482   49328   6842     98.9    1.270
-01.0   96    40.89   2550    2527   50772   6892     99.1    1.254
+00.0   97    41.30   2573    2572   52257   6940     99.3    1.238
+01.0   98    41.71   2595    2617   53786   6987     99.4    1.223  ! Near Maximum !
+02.0   99    42.13   2618    2663   55360   7031     99.6    1.207  ! Near Maximum !
+03.0  100    42.54   2640    2708   56979   7072     99.7    1.192  ! Near Maximum !
+04.0  101    42.95   2662    2754   58647   7112     99.8    1.178  ! Near Maximum !
+05.0  102    43.37   2685    2801   60365   7149     99.8    1.163  ! Near Maximum !

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba     97    41.30   2668    2766   61310   6703    100.0    1.160  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     97    41.30   2439    2311   43422   6882     95.0    1.340

Dwh7271 · Apr 6, 2019

Here it is a little higher

Code:

Cartridge          : .308 Win. (SAAMI)
Bullet             : .308, 175, Sierra HPBT MatchK 2275
Useable Case Capaci: 48.846 grain H2O = 3.171 cm³
Cartridge O.A.L. L6: 2.855 inch = 72.52 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : IMR 4064 ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-10.0   90    38.25   2404    2246   42221   6536     97.7    1.362
-09.0   91    38.68   2428    2290   43497   6599     98.0    1.344
-08.0   92    39.10   2451    2335   44810   6659     98.2    1.326
-07.0   93    39.53   2475    2380   46163   6718     98.5    1.308
-06.0   94    39.95   2499    2426   47555   6775     98.7    1.291
-05.0   95    40.38   2522    2472   48988   6829     98.9    1.274
-04.0   96    40.80   2545    2518   50464   6882     99.1    1.257
-03.0   97    41.23   2569    2564   51984   6932     99.3    1.241
-02.0   98    41.65   2592    2610   53550   6980     99.4    1.225  ! Near Maximum !
-01.0   99    42.08   2615    2657   55163   7025     99.5    1.209  ! Near Maximum !
+00.0  100    42.50   2638    2704   56825   7068     99.7    1.194  ! Near Maximum !
+01.0  101    42.93   2661    2751   58537   7109     99.8    1.179  ! Near Maximum !
+02.0  102    43.35   2684    2799   60301   7148     99.8    1.164  ! Near Maximum !
+03.0  103    43.78   2707    2847   62120   7184     99.9    1.149  !DANGEROUS LOAD-DO NOT USE!
+04.0  104    44.20   2729    2895   63996   7217    100.0    1.135  !DANGEROUS LOAD-DO NOT USE!
+05.0  105    44.63   2752    2943   65930   7248    100.0    1.121  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba    100    42.50   2729    2894   66645   6795    100.0    1.120  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba    100    42.50   2507    2442   47205   7077     96.0    1.291

longrangehunter · Apr 7, 2019

I appreciate you taking the time to run that for me Dewey, so Thanks!

I stopped loading my cases once my velocity hit 2,725+ since Hodgdon listed that as their max, only with a lot more powder! I know around the 44.1 mark in Lapua brass and that bullet can get hot pretty quick depending on the gun.

Thanks buddy!

Dwh7271 · Apr 7, 2019

Anytime

longrangehunter · Aug 28, 2019

So like most during summer time I disappear, but I'm back at this again only with a different barrel. I now have a 1:10" Bartlein 24" barrel made by WinTech for AI I'm testing out.

This barrel has a short throat though, 2.780 COAL just touches the lands w/the 175 SMK. The previous load using 43.5 grains of IMR-4064 seated to 2.760" COAL still produces the same large 5/8" bughole as the previous 1:12" 7.62 barrel.

I've messed around with dropping the charge from 42.5 up to 43.5 and in the middle alot at 42.7 @ .020" off the lands. They all are right at the 5/8" MOA @ 100 yards in New Lapua Brass. Seems like maybe this is all it may do as a military rifle was meant to do, but I'll still have to see what it can do with a little more work.

I don't see how to get it near the OBT numbers listed and others have had great luck in the 42-43.5 range using IMR-4064 and the 175 SMK, so we shall see.

longrangehunter · Sep 13, 2019

So after I put a few more rounds through the new barrel I did settle on a load at 42.5 IMR-4064 F210M and the 175 SMK @ 2.170" CBTO = to 2.760" COAL....... Kinda short and a compressed load but it's now printing right around the 3/8" moa mark going roughly 2,700 fps.

So I've had a fondness for the BERGER 185 Juggernaut OTM Tactical bullets ever since I used them in my 300 Jarrett I no longer own. Long story short I decided to test them in the 308 Win in this barrel and pulled out some VarGet since I know this powder can work really well with this weight bullet in the 308 Winchester.

I started with 42.3 and only got to 42.6 before I stopped since I had one hole and the speed was already at the expected velocity, 2,600 fps @ 20' from the muzzle. The five shots all went into a nice bughole and settled on 42.3 for further testing.

So this got interesting since I bought a few thousand CCI #34's for this purpose, and another 10 pounds of VarGet. This combination lowered the ES to 6, and the SD to 2....... Which I was thrilled to see having just spent $500 on this project.

I don't usually use a Hot primer unless I'm using a ball powder or spherical powder but VarGet is small enough that I thought this type of primer would work really well in this case.... i.e. it's design for the 7.62 so why not right!?!

You'll notice they really didn't do much to lower the ES/SD using them with the IMR-4064 load, but I didn't test them with the F210M primers I tuned the load with and they shot better with that primer so I'd have to say they would have been better velocities over the Oehler screens.