[thornblom]

IMR has developed a new super accurate, super consistant bench rest and long range powder that can be used in all the current bench rest calibers and most of the long range calibers including the .223 REM and the .308 WIN. In 2009 this powder was used to win several important bench rest,
F class , F-TR class, and 1000 yard matches. This powder is supposed to be the ultimate as far as being NOT sensitive to temp variations. It was tested form -40 degrees F to + 165 degrees F by IMR and showed no apprecialbe variation in velocity.

There was a long range course put on in Austrailia and they used 175 grain Remington Premier Match ammo to shoot targets from 100 yards out to 1219 yards with various .308 rifles. This ammo was the most consistantly accurate at all ranges of any ammo used that day.

I don't know the exact load but my best educated guess is that it looks like this:

Case: Remington .308, 2.005" long
Primer: Remington 9 1/2 Large Rifle
Bullet: 175 grain Sierra Match King
Powder: 41 to 41.5 grains of IMR-8208 XBR, as interpolated from the Hodgdon site, 39 grains = 2511 ft/sec, 42.5 grains = 2664 ft/sec
COL: 2.800"
Factory velocity claim is 2609 ft/sec. This powder may start showing up in gun stores this month.
Some of the matches won in the US were with handloaded .308 ammo loaded with one consistant charge weight. They were not varying charge weights as the temps changed. With this powder they didn't have to. I want some!

Sincerely,
Dave (Bubba) Thornblom

 

[jerrschmitt]

I've been trying to find some and pick on my local gunshop owner weekly in my search for that stuff. The guys on 6BR and BR.com have been talking about it for months but we can't seem to get it locally.

 

[Quick]

The ammo in question, there was a 3FPS variation between 0 Deg C and 26 Deg C. I was using a different load (Highland 155gr Palma SMK) and had an 83FPS difference at the same temp. Ill try to get Quietman on here to share his views. It was his ammo and his rifle.

the 175gr Rem Match is very consistent ammo. Grab some if you can.

 

[thornblom]

OK gentlemen, this powder has been out for awhile. Have any of ya'll developed any good loads with this powder yet. I think it is still hard to find but worth the look when you do find it. I have garnered this info from other sites so use with caution.

155 grain SMK: 41 grains of IMR-8208 XBR to 45.3 grains/ 2619 fps to 2854 fps, 44.9 grains is supposed to be the balance point or accuracy load at 2829 fps.

168 grain SMK: 39 grains of IMR-8208 XBR to 43.3 grains/ 2493 fps to 2707 fps, 42.8 grains is
supposed to be the balance point or accuracy load at 2675 fps.

175 grain SMK: 39 grains of IMR-8208 XBR to 42.5 grains/ 2511 fps to 2664 fps, 42.5 grains is
supposed to be the balance point or accuracy load at 2664 fps.

If any of ya'll have worked with this powder and these bullets, please post results so we can see some actual velocities and targets.

Thanks.

Sincerely,
Dave (Bubba) Thornblom

 

[jerrschmitt]

I've been trying to find it for six months or more. My local guy can't even order it. I think the bench rest and F shooters are buying it up as fast as it's made.

 

[thornblom]

I have a great load that I use with this powder.

Case: winchester, 2.005" in length
Primer: winchester WLR
Bullet: 168 gr SMK
Powder: 41.5 gr IMR-8208-XBR
COL: 2.825"
MV: 2603.5 ft/sec

5 shot, 100 yard group, including the cold bore shot .212" wide x .232" tall. Group was shot using my Harris bipod.

Sincerely,
Dave (Bubba) Thornblom

 

[308isgreat]

Great info Dave! I'm going to find some and work up some loads for my SPS Tac and see how it works. Been using Reloader 15 with great success, but this new powder looks promising. Your load looks like a good one to work with. What was the barrel length you fired the loads through?

 

[thornblom]

My rifle is a Remington 700 VSF .308. Heavy 26" fluted barrel with 1 turn in 12" twist. HS stock.

Sincerely,
Dave (Bubba) Thornblom

 

[308isgreat]

Thanks Dave! I have a 20" SPS Tac so I will need to work up some for this length because my velocities will be a bit lower then a 26" barrel.

 

[desertdog]

Just scored some of this stuff, cant wait to work up some loads.

The Plan
Speer HPBT Match 168gr.
BR2 Primers
New Rem. Brass
8208 XBR

I have the 26" 1/12 twist bbl.

Any ideas where to start, Im thinking 39gr -40gr?

 

[Winxp_Man]

Cartridge          : .308 Win.
Bullet             : .308, 175, Sierra HPBT MatchK 2275
Useable Case Capaci: 47.974 grain H2O = 3.115 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length      : 26.5 inch = 673.1 mm
Powder             : IMR 8208 XBR

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0   76    33.60   2219    1913   31586   5185     95.5    1.639
-18.0   78    34.44   2267    1997   33529   5315     96.3    1.600
-16.0   80    35.28   2315    2083   35585   5440     97.0    1.563
-14.0   82    36.12   2363    2169   37759   5558     97.6    1.526
-12.0   84    36.96   2410    2257   40058   5670     98.1    1.485
-10.0   85    37.80   2457    2346   42489   5775     98.6    1.446
-08.0   87    38.64   2504    2436   45061   5873     99.0    1.409
-06.0   89    39.48   2550    2527   47782   5964     99.4    1.373
-04.0   91    40.32   2596    2619   50662   6047     99.6    1.338
-02.0   93    41.16   2641    2711   53711   6122     99.8    1.305  ! Near Maximum !
+00.0   95    42.00   2686    2804   56940   6188     99.9    1.273  ! Near Maximum !
+02.0   97    42.84   2731    2898   60362   6246    100.0    1.242  !DANGEROUS LOAD-DO NOT USE!
+04.0   99    43.68   2775    2993   63991   6298    100.0    1.213  !DANGEROUS LOAD-DO NOT USE!
+06.0  101    44.52   2819    3088   67842   6347    100.0    1.184  !DANGEROUS LOAD-DO NOT USE!
+08.0  103    45.36   2862    3184   71931   6395    100.0    1.156  !DANGEROUS LOAD-DO NOT USE!
+10.0  104    46.20   2905    3280   76278   6441    100.0    1.129  !DANGEROUS LOAD-DO NOT USE!

 

[Winxp_Man]

Hope this will help a little.

 

[308isgreat]

Yeah buddy......Winxp_Man scored a couple pounds yesterday and he is bringing one by so we can run it! Thanks Aron!
Always jacked to work up more loads!

 

[desertdog]

I found some at Bass Pro Shops, of all places! None of the gun shops here had even heard of it. Not a lot of reloading places here in town.

 

[Winxp_Man]

This will work for rifles that you are reloading with Winchester Brass that has been once fired. I am not responsible for any thing that you do out of what is stated here. This is for brass that can fit 57.33 gr of H2O. I would start low anyways and see how your rifle does and climb form there.

This is for the 175 SMK bullet.

Cartridge          : .308 Win.
Bullet             : .308, 175, Sierra HPBT MatchK 2275
Useable Case Capaci: 49.311 grain H2O = 3.202 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length      : 20.0 inch = 508.0 mm
Powder             : IMR 8208 XBR

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0   77    35.04   2135    1772   33538   7402     94.2    1.355
-18.0   79    35.92   2184    1853   35635   7605     95.1    1.322
-16.0   81    36.79   2232    1936   37853   7802     95.9    1.290
-14.0   83    37.67   2280    2021   40200   7990     96.6    1.252
-12.0   85    38.54   2328    2107   42683   8169     97.3    1.217
-10.0   87    39.42   2376    2194   45312   8339     97.9    1.184
-08.0   89    40.30   2424    2282   48094   8499     98.4    1.152
-06.0   91    41.17   2471    2372   51040   8649     98.9    1.121
-04.0   92    42.05   2518    2463   54161   8788     99.2    1.091  ! Near Maximum !
-02.0   94    42.92   2564    2555   57468   8916     99.5    1.062  ! Near Maximum !
+00.0   96    43.80   2611    2648   60974   9031     99.8    1.034  ! Near Maximum !
+02.0   98    44.68   2657    2742   64695   9134     99.9    1.008  !DANGEROUS LOAD-DO NOT USE!
+04.0  100    45.55   2702    2837   68645   9225    100.0    0.982  !DANGEROUS LOAD-DO NOT USE!
+06.0  102    46.43   2747    2933   72842   9303    100.0    0.957  !DANGEROUS LOAD-DO NOT USE!
+08.0  104    47.30   2792    3030   77305   9378    100.0    0.933  !DANGEROUS LOAD-DO NOT USE!
+10.0  106    48.18   2837    3127   82056   9450    100.0    0.910  !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     96    43.80   2700    2833   71322   8703    100.0    0.970  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     96    43.80   2481    2392   50765   9043     96.3    1.120

 

[Winxp_Man]

Ok same thing here but the bullet has been changed to the 168 SMK. Remember the brass that I'm doing these numbers for were once fired Winchester brass that I posted the capacities in the handload thread.

Cartridge          : .308 Win.
Bullet             : .308, 168, Sierra HPBT MatchK 2200
Useable Case Capaci: 50.220 grain H2O = 3.261 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length      : 20.0 inch = 508.0 mm
Powder             : IMR 8208 XBR

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0   77    35.84   2180    1773   33411   7527     93.6    1.330
-18.0   79    36.74   2230    1855   35508   7738     94.6    1.298
-16.0   81    37.63   2280    1939   37729   7941     95.4    1.266
-14.0   83    38.53   2330    2024   40080   8136     96.2    1.229
-12.0   85    39.42   2379    2111   42569   8323     96.9    1.195
-10.0   87    40.32   2428    2199   45204   8501     97.6    1.162
-08.0   89    41.22   2477    2289   47996   8668     98.1    1.130
-06.0   91    42.11   2526    2380   50953   8825     98.6    1.099
-04.0   93    43.01   2574    2472   54087   8971     99.0    1.070  ! Near Maximum !
-02.0   95    43.90   2622    2565   57411   9105     99.4    1.041  ! Near Maximum !
+00.0   97    44.80   2670    2660   60937   9228     99.7    1.014  ! Near Maximum !
+02.0   99    45.70   2718    2755   64680   9337     99.8    0.988  !DANGEROUS LOAD-DO NOT USE!
+04.0  101    46.59   2765    2852   68656   9434    100.0    0.962  !DANGEROUS LOAD-DO NOT USE!
+06.0  103    47.49   2812    2949   72884   9517    100.0    0.938  !DANGEROUS LOAD-DO NOT USE!
+08.0  105    48.38   2858    3047   77383   9591    100.0    0.914  !DANGEROUS LOAD-DO NOT USE!
+10.0  106    49.28   2904    3147   82175   9662    100.0    0.891  !DANGEROUS LOAD-DO NOT USE!

 

[twosmokinspades]

There has been some interest in lighter bullets in 308 lately so I loaded some 125 g Nosler Ballistic Tips and out I went. I shot 1 group in of my favorite load 168 SMK for reference. All shots at 100 yards.

Stupid computer!!! soon its going on the 100 y line! its not loading the pictures

Here is the tecnical detail
Load data Remington LTR .308

125 g Nosler ballistic tip crono 2962 fps
IMR 8208 47.5 2942 fps
OAL ??? 2966 fps
Fed 210m primers 2969 fps
Win brass on it 9th reload

 

[twosmokinspades]

Try this

 

[twosmokinspades]

And again

 

[twosmokinspades]

Seems to be working