IMR 4198 in a .308 Winchester Bolt Gun

Hello to The Reloaders Network!

BigE here!

I thought I would try something different in my 308 target rifle. It started as a Savage 11VT that was found to be a little unsafe with the original barrel (short throat with rifling at 0.307″ would pop primers on factory loads occasionally and was almost always a hard bolt close due to jam), and so I replaced it with a Shilen Varmint taper barrel. I was shooting 178gr ELD-X bullets at 2700 fps. I ordered a 24″ barrel (the original was a 26″). All of a sudden it seemed to lose the handle on my reloads and a replacement Criterion 28″ bull was ordered. It was found, once the barrel was in hand, that the bullets were at fault. I had several bad boxes that were all of a sudden 4 MOA. The last box of 100, which was loaded in a lot of 200 pieces of brass at the same time as another, was magically back at 3/4 MOA and awesome, but alas, the new barrel was here and I installed it. It wears a Bell & Carlson M40 stock and Harris Bi-pod with either a 10×42 Mil-Quad SWFA SS scope or a Primary Arms 4-14×44 308 HUD.

I initially did a work up of 155 Lapua Scenars and Lapua brass replacing my Hornady 308 Match brass.  The workup did pretty dang good with Shooter’s World Propellants Precision Rifle Powder. All brass was match prepped. Annealed, trimmed, chamfered, deburred, flash holes uniformed and primer pockets uniformed.

All loads at 2.886″ which is 0.005″ from the lands.

However after receiving my copy of QuickLOAD and looking into other odd stuff, I came across the IMR-4198 in a 308 as a possible load with a maximum load of just over 38gr of powder behind a 155 Scenar.

IMR 4198 in a .308 Winchester Bolt Gun 1 IMR 4198 in a .308 Winchester Bolt Gun 3

So I went to the range and shot them and results are as follows….

PC                               Velocity                     SD                ES

35                                2633                           23                 54

35.5                             2722                           18                 45

36                                2745                            5                   12

36.5                             2749                           16                 43

37                                2807                           14                  34

37.5                            2851                            16                  39

38                               2865                           11                   39

 

IMR 4198 in a .308 Winchester Bolt Gun 5                    IMR 4198 in a .308 Winchester Bolt Gun 7

Those are the seven groups I shot left to right with left two reversed.  35.5, 36.5, & 37.5 where the good groups.

 

However I did shoot 15 of the 35 in the end into a nicer group than the first group of 2.05″.

IMR 4198 in a .308 Winchester Bolt Gun 9

So clearly that first group was too much time off the rifle!!!!

At this time I also did a proof load group of 45.3 gr of SWP Precision Rifle and shot this…

IMR 4198 in a .308 Winchester Bolt Gun 11

This is at 2897 fps. SD 11. Little higher than last time out at 8. hmmm… Still easily good enough for a 308 to 1000 yards though.

 

 

In the end the brass showed no indication of pressure from the primers and was as clean as when it went in but was a little sticky coming out. This was a common problem all through the charge weights. I guess in the end I would not recommend the loads.

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John Fazer
John Fazer

Nice write up.

Joe S.
Joe S.

That’s interesting. I recently met a gentleman at the range who was using and suggesting IMR 4198. He was shooting .308 with it. my experience with IMR 4198 I’ve used it in .32 Winchester Special under a Lyman 165gr cast lead Flat Nose, powder coated, sized. Once fired brass sized, trimmed, chamfered. A ten shot test had 66ft/sec spread at around the 1,700 FPS mark 20.5 gr of IMR 4198. Using a Winchester Model 94. I thought that was pretty good. I haven’t messed with that load or had time to do a second test. In my .22 Hornet… I’m… Read more »

cdcoutdoor
cdcoutdoor

I’ve tested imr4895 with the 168g eldm. I had good results. unfortunately I didn’t have my crono out to see the data.. I’ll be testing the 168 tmk soon. I’m not sure what powder I’m going to use yet.

Loads of Bacon
Loads of Bacon

Great to see you posting here BigE!
I think I got QuickLOAD a couple days after you did….it’s a lot of fun to play with.
It looks like you may be on to something with that Precision Rifle load.