IMR8208XBR Range Day

[nosler06]

Well I think I have found a powder that I can and seems to work well in an old Browning BLR .308. I finally found a pound of powder IMR8208XBR and then started to make up some test loads. I have not changed the OAL at all with bullet seating. I headed to the range with Osprey78 and had mixed bag of weather. Sun, rain and yes snow. I have my ideas as to which load I might play with, but would like to see what others can extrapolate as a load which is workable.



















All are 100yd targets, 165gr Speer Hot Core bullets, CCI200 primers and Winchester brass once fired.

 

[Osprey78]

39.5 grains perhaps? The load data from Hodgdon shows that it would be in the mid 2500 fps range. Even the 40 grain load would do well with some tweaking.

It was fun, buddy!

8)

 

[SJB358]

Cartridge : .308 Win. (SAAMI)
Bullet : .308, 165, Speer SP 2035
Useable Case Capaci: 49.336 grain H2O = 3.203 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 79 36.00 2209 1789 34239 7556 93.5 1.302
-18.0 81 36.90 2260 1872 36426 7767 94.5 1.270
-16.0 83 37.80 2311 1957 38746 7971 95.3 1.236
-14.0 85 38.70 2362 2044 41205 8167 96.1 1.200
-12.0 87 39.60 2413 2132 43814 8353 96.9 1.166
-10.0 89 40.50 2463 2222 46581 8530 97.5 1.133
-08.0 91 41.40 2513 2314 49517 8697 98.1 1.102
-06.0 93 42.30 2563 2406 52634 8853 98.6 1.072
-04.0 95 43.20 2612 2500 55944 8998 99.0 1.042 ! Near Maximum !
-02.0 97 44.10 2662 2596 59462 9130 99.4 1.014 ! Near Maximum !
+00.0 99 45.00 2711 2692 63203 9250 99.6 0.987 ! Near Maximum !
+02.0 101 45.90 2759 2790 67183 9356 99.8 0.961 !DANGEROUS LOAD-DO NOT USE!
+04.0 103 46.80 2808 2888 71422 9450 100.0 0.936 !DANGEROUS LOAD-DO NOT USE!
+06.0 105 47.70 2856 2988 75941 9529 100.0 0.912 !DANGEROUS LOAD-DO NOT USE!
+08.0 107 48.60 2904 3089 80764 9599 100.0 0.888 !DANGEROUS LOAD-DO NOT USE!
+10.0 109 49.50 2951 3190 85916 9665 100.0 0.865 !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 99 45.00 2807 2886 74073 8921 100.0 0.925 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 99 45.00 2573 2426 52502 9228 95.9 1.070


Here is what QL looks like for your combo. I would imagine you'll have a 2nd node as you creep up some. If you have any ability to alter the seating depth, I am betting you'll come into a good load. I hear and see alot of great things from 8208.

 

[DrMike]

I would be inclined to look for a second node as Scotty suggests. If there is no difficulty extracting at the charge of 42.5 grains, I would step up in half grain increments to look for a second node. There is no question but that your groups at either 39.5 or 40.0 grains are decent. Since you really can't play much with seating depth, you're compelled to worked with tweaking charge weights. Still more than good enough for moose at reasonable yardages.

 

[skidmark]

Try 41.8 at 2.800......
Nosler 165 BT's or 165 SGK's
Dr. Mike was right 8208 was a decent powder for .308
almost as good as Varget.
I got pressure before I got a 2nd node in my 700
it builds pressure fast be careful. That's my experience
in my gun.

 

[nosler06]

Try 41.8 at 2.800......
Nosler 165 BT's or 165 SGK's
Dr. Mike was right 8208 was a decent powder for .308
almost as good as Varget.
I got pressure before I got a 2nd node in my 700
it builds pressure fast be careful. That's my experience
in my gun.

DrMike

I would be inclined to look for a second node as Scotty suggests. If there is no difficulty extracting at the charge of 42.5 grains, I would step up in half grain increments to look for a second node. There is no question but that your groups at either 39.5 or 40.0 grains are decent. Since you really can't play much with seating depth, you're compelled to worked with tweaking charge weights. Still more than good enough for moose at reasonable yardages.

I am very certain that there would be a second node with a higher charge, but this being an older lever action (I know the BLR to be a strong action) I am leaning towards a lighter than heavier load. I had no problems extracting any of the catridges all the way up to 42.5grs. The Hodgdon data states that 42.8grs was max. I may play some more with the loads and try 41.8grs. Once I get a nice grouping load I will then do the tweaking with 165gr Nosler Parts. The 165gr NP will be the hunting round as I am a tried and true Nosler believer, and am making Osprey78 into one a step at a time. Lol. I am limited as to the OAL tweaking that can be done as the older mag for the BLR is short. I also look at the 41.5gr load and if I am incorrect please let me know, but a vertical shot strand is velocity variations and not a bad thing?

 

[SJB358]

If you give me the H20 capacity of your cases, I will run the QL for your specific rifle. It'll give you a decent idea where your top end is.

 

[skidmark]

but a vertical shot strand is velocity variations and not a bad thing?

If your are shooting thru a chrony you would see if you are having
velocity variation with the vertical, I would recheck your rifle rests
and how it sits in the bags and your hold.
If its any consolation I have found less than max loads to be the most
accurate for groups but you will have to make some trade off to maintain
good hunting velocities. I had an early .308 BLR and it shot well although
I no longer have it. looks like your are coming into a nice load for that
lever. Would be interested in knowing the speed of that 39.5 its great.
Just my 2 cents.

 

[nosler06]

Did some measuring today. I chamber seated a bullet today to see what the OAL total was to the lands in my Browning BLR. I measured 2.912" OAL to lands. The magazine length is 2.895" OAL. I guess there is no way to be 100 off the lands for my OAL. I think that I might have to try 2.800" again and see if it will cycle through without jamming on the front edge of the magazine. I was down at 2.7450" OAL before. If I can I will try the 41.8gr load and see what groups I can get out of it. I may try some different shortened lengths just to see if this old BLR likes a jump to the lands. It might be that the 41.5gr grouping is truly velocity affected for the vertical pattern.

 

[bobnob]

I could live with that group at 39.5 as long as it was consistently as good as that. To know speed would be interesting.

Even at 2500fps a 165g bullet is gonna be hell on any deer or hog. A little more speed would be just a little better too perhaps.

My present 308 I am loading 150g Corelokts at a measly 2600fps - its a really ancient 1897 made Mauser so I want to keep pressure down - and those things punch on through and have no trouble handling pigs and big billy goats out well past 200 yards. You don't need big speed all the time it seems.

 

[SJB358]

Did some measuring today. I chamber seated a bullet today to see what the OAL total was to the lands in my Browning BLR. I measured 2.912" OAL to lands. The magazine length is 2.895" OAL. I guess there is no way to be 100 off the lands for my OAL. I think that I might have to try 2.800" again and see if it will cycle through without jamming on the front edge of the magazine. I was down at 2.7450" OAL before. If I can I will try the 41.8gr load and see what groups I can get out of it. I may try some different shortened lengths just to see if this old BLR likes a jump to the lands. It might be that the 41.5gr grouping is truly velocity affected for the vertical pattern.

I would try to work small seating depths with your 41.8/42.0 grain charge. Work it in .010 at a time and see what happens. I know it is a little frustrating but you will start to see where the bullet wants to be.

41.8 is a fairly mild charge so once you find the seating depth the rifle likes, you can incrementally push the powder charge up seeing if accuracy sticks for it.

It does look like you have some ability to work with the bullet, so I would exhaust that first in small changes. You'll nail it, your Browning is just testing you right now... :grin: