Tried IMR4166 Enduron powder in my .308

[CFJunkie]

After PaddyD's comment in a post a few days ago about his success with IMR4166 powder in his .308, I finally got around to loading some IMR4166 for my Savage 10 FP .308.
the 10 FP is an old rifle (2009 vintage) with a relatively new fluted target barrel that I had Savage install after the original barrel started to show some effects of throat erosion on accuracy after more than 6500 rounds.

With 5 round groups at 100 yards in temperatures from 35 to 43 degrees and winds from 5 to 8 mph:
1 shot 11 groups with 4 closely matched loads of IMR4166 using 168 Tipped Match King (TMK) bullets seated out between 2.850 and 2.868 O.A.L. at velocities around 2620 fps.
Average of all 11 groups was 0.410. This was the second best Powder-Bullet combination average that I have ever achieved with this rifle.
The average of the previous 168 grain loads with 168 TMKs was 0.453 for 83 groups with 4 different powders.

The best powder bullet combination was 0.399 with 155 TMKs and IMR4064 powder. It is still in first place.
The best powder bullet combination average with 168 TMKs with IMR4064 powder is 0.487.
The best previous powder bullet combination average with 168 TMKs was with N140 powder is 0.433.

That gives IMR4166 powder first place among the 168 powder bullet combinations.
IMR4166 powder will shoot pretty well in an old .308.

[PaddyD]

After PaddyD's comment in a post a few days ago about his success with IMR4166 powder in his .308, I finally got around to loading some IMR4166 for my Savage 10 FP .308.
the 10 FP is an old rifle (2009 vintage) with a relatively new fluted target barrel that I had Savage install after the original barrel started to show some effects of throat erosion on accuracy after more than 6500 rounds.

With 5 round groups at 100 yards in temperatures from 35 to 43 degrees and winds from 5 to 8 mph:
1 shot 11 groups with 4 closely matched loads of IMR4166 using 168 Tipped Match King (TMK) bullets seated out between 2.850 and 2.868 O.A.L. at velocities around 2620 fps.
Average of all 11 groups was 0.410. This was the second best Powder-Bullet combination average that I have ever achieved with this rifle.
The average of the previous 168 grain loads with 168 TMKs was 0.453 for 83 groups with 4 different powders.

The best powder bullet combination was 0.399 with 155 TMKs and IMR4064 powder. It is still in first place.
The best powder bullet combination average with 168 TMKs with IMR4064 powder is 0.487.
The best previous powder bullet combination average with 168 TMKs was with N140 powder is 0.433.

That gives IMR4166 powder first place among the 168 powder bullet combinations.
IMR4166 powder will shoot pretty well in an old .308.

Must be something about those FP's. I think mine, a 110FP, was born about 1989 ? Still with the orig barrel and it absolutely loves those 175 SMK's and IMR 4064 @ about 2,600 fps. Last group out of it with that combo was a startling .206" @100 yds. Mine does wear a Choate Varmint stock as the original flimsy plastic one was a total P.O.S. . I think it's nearing about 6,000 rds down the tube. Still waiting for it to give up the ghost.

[Evlshnngns]

Thanks for posting.

[deerhunter99]

I have a can of that i have never load anything with it, I had better get busy and start !!!

[CFJunkie]

PaddyD,

I agree that there is something about the old FPs.
I changed my stock on my 10 FP after the barrel was replaced to an adjustable Bell & Carlson aluminum pillar bedded stock, not because the factory stock was particularly flimsy, but because I eventually noticed that it was a bit too short for my long arms.
Turns out, I noticed that I was sliding forward toward the scope during recovery from recoil and that moving closer moved my next point of impact slightly higher causing vertical stringing.

My 10 FP seems to like 150 to 168s more than the heavier 175s yours likes.
But my 10 FCP-K .308

with an Accu-Stock,

that is about 4 or 5 years newer, prefers 175s, 190, 195s and 200s probably like your 110 FP.
Both have 24 inch barrels but the new 10 FP barrel is suppressor ready and the 10 FCP-K has a muzzle brake.

Every barrel seems to have its own preferences when it comes to bullet weights.

Both shoot the Sierra TMKs better than any other bullet type as long as the bullet weight is what they like.
But they like the TMKs seated out about 0.070 to 0.080 further than the SMKs, Nosler CCs or Bergers.

Of all the powder bullet combinations that I have tried, both rifles have the first 10 to 12 favorites made up of all TMK bullets followed by all the rest of the other bullets, but the lighter or heavier weight TMKs are at the top of the rifle's respective tables.

[PaddyD]

Tried to post up my target from today, but I must be doing something wrong. Today it preferred the 150's over 175SMK's The 150's shot a pretty little 0.267" cloverleaf, but the best for the 175's was 0.351" Used IMR4064 with both . The 150's are factory second Hornady Interlocks from MidwayUSA. The 175's are pulled from some old M118LR military ammo I got from RMR bullets out in Idaho. RMR is a fantastic company by the way. Always ship free. Wish I knew how to post pics here. When I try all it posts is what looks like code.

[CFJunkie]

The 10 FP shot so well on Saturday with IMR4166 that I went to the range this morning with the 10 FCP-K to see how it would do with IMR4166.
The 10 FCP-K has a 24 inch barrel with a 2.125 inch muzzle brake.
I loaded 175 grain TMK bullets in temperatures from 39 to 44 degrees with winds from 1 to 4 mph with 4 closely matched loads of IMR4166 seated out between 2..836 and 2.858 inches at muzzle velocities between 2336 to 2356 fps.

Average of 10 five-round groups was 0.399 inches which was the best average for a powder-bullet combination for this rifle.
I attribute some of the better performance compared to the 10 FP to the lighter winds with fewer gusts.
The previous best powder-bullet combination average with the 10 FCP-K was 0.441 with IMR4064 powder with 168 grain TMKs and 0.444 with IMR4064 powder with 175 grain TMKs.

IMR4166 is proving to be very accurate on both rifles.

[PaddyD]

I was getting sub 1/2 MOA with it too, but for some reason started getting ejector impressions on cases. Don't own a chronograph to test any velocities. Haven't done anything with it since, but I think I'll play with the 4166 some more tonight and test tomorrow.

[CFJunkie]

Just an update on using IMR4166 in my 10 FP with 155 grain TMK bullets.
Loaded at 2558 fps at 2.866 O.A.L. and shot 12 groups with 4 different loads at between 38 and 41 degrees with pretty calm winds.
The 12 groups averaged 0.410 with a best load of 0.359.
That average was identical to the average I shot with IMR4166 using the 168 grain TMKs.

Pretty good results with IMR4166, so far.

[CFJunkie]

Here is a summary of all the IMR4166 loads for two rifles with pertinent data as of yesterday Jan 4th, 2019.
IMR4166 is still doing pretty well with both rifles.
Yesterday improved the 10 FP with two 168 grain TMKs loads that averaged 0.400 combined.
Yesterday slightly increased the 10 FCP-K average with one load of 175 TMKs that averaged 0.496.

Rifle 10 FP 24-inch barrel
155 TMK
Powder Charge O.A.L. Trim Vel exit time Temp Avg. # grps.
IMR4166 42.9 gr 2.862 case 2.009 2557 wf 1.256 * 38/40 deg F. 0.446 3
IMR4166 42.9 gr 2.868 case 2.007 2558 wf 1.256 * 42/40 deg F. 0.456 3
IMR4166 42.9 gr2.868 case 2.005 2558 wf 1.256 * 43/40 deg F. 0.359 3
IMR4166 42.9 gr 2.866 case 2.001 2559 wf 1.256 * 44/41 deg F. 0.379 3
Average = 0.410 for 10 groups
Best powder is IMR4064 with 0.399 average for 10 groups.

168 TMK
Powder Charge O.A.L. Trim Vel exit time Temp Avg. # grps.
IMR 4166 42.1 gr 2.865 case 2.013 2516 wf 1.256 * 37/34 deg F 0.366 3
IMR 4166 42.1 gr 2.865 case 2.010 2518 wf 1.256 * 39/37 deg F. 0.451 2
IMR 4166 42.2 gr 2.860 case 2.008 2518 wf 1.256 * 34/35 deg F. 0.412 3
IMR 4166 42.2 gr 2.866 case 2.006 2519 wf 1.256 * 37/37 deg F. 0.403 4
IMR 4166 42.2 gr 2.868 case 2.004 2520 wf 1.256 * 40/39 deg F. 0.431 2
IMR 4166 42.2 gr 2.871 case 2.000 2522 wf 1.256 * 43/41 deg F. 0.399 2
Average = 0.407 for 16 groups
Next best powder is N140 with 0.436 average for 9 groups.

Rifle 10 FCP-K 24-inch barrel w muzzle brake
175 TMK
Powder Charge O.A.L. Trim Vel exit time Temp Avg. # grps.
IMR4166 39.5 gr 2.836 case 2.012 2356 wf 1.366 * 32/39 deg F 0.336 1
IMR4166 39.5 gr 2.847 case 2.011 2356 wf 1.366 * 37/40 deg F 0.374 3
IMR4166 39.5 gr 2.850 case 2.011 2353 wf 1.366 * 40/41 deg F 0.430 3
IMR4166 39.5 gr 2.858 case 2.009 2355 wf 1.366 * 42/44 deg F 0.496 3
IMR4166 39.7 gr 2.866 case 2.013 2354 wf 1.366 * 36/33 deg F 0.457 2
IMR4166 39.7 gr 2.863 case 2.010 2354 wf 1.366 * 36/35 deg F 0.407 4
IMR4166 39.7 gr 2.865 case 2.012 2354 wf 1.366 * 36/34 deg F 0.395 2
Average = 0.425 for 18 groups.
Next best powder is IMR4064 with a 0.441 average for 25 groups.

[Robinhood]

Good info CF. Might as well include the brass and the primer..........

[CFJunkie]

Sorry I left that information out.
All loads used Lapua brass and Federal 210M match primers.

Lapua brass and 210M primers are all I shoot now in my .308s.
Over the years, I have experimented with Norma, Nosler, Winchester, Remington, and Federal brass - each shot with loads using Federal 210, and Winchester LRP primers.
Lapua lasted longer (over 20 reloads on average) without annealing usually until the primer pockets wore out without the neck splitting that I experienced on the other brass under the same conditions. Lapua might be more expensive than all but Norma, but it lasts longer than any of the other brass - enough to become the most cost effective as well as the most accurate.

For my loads, the 210M primers are at the top of my powder-bullet accuracy charts so I decided not to fight the data on either of those choices.

[strut64]

I would like to hear about success with other calibers. 223 Rem and 30-06 are what I am thinking of.

[CFJunkie]

I would think that IMR4451 would be a better choice than IMR4166 with a .30-06 or a .270 since both of my rifles in those calibers really like IMR4350.
IMR4451 is the Enduron equivalent to IMR4350 according to IMR's data sheets.
IMR4166 is the Enduron equivalent to IMR4064 according to IMR's data sheets.

As for using IMR4166 in a .223 Rem, I would suggest trying IMR4166 with heavier bullets.
For lighter bullets from 52 to 55 grains, powders in the H335 and N133 range seem to shoot much more accurately in my rifles.

I don't have a bolt action rifle in .223 in a fast twist barrel so I haven't tried shooting heavier bullets in the 69 to 77 grain range in a bolt action .223.

For heavier bullets, my Les Baer .223 with a 1:8 twist barrel likes IMR4064, Varget, N140, and H4895 with 69 and 77 grain bullets and it should also like IMR4166.
I haven't tried IMR4166 Enduron yet but that is on the agenda for the future with the Les Baer .223 with 69 and 77 grain bullets, probably sometime in the spring.

[GaCop]

Bought a pound of 4166 to try in my 6.5 Creedmoor but load data only shows it being used with light bullets in the Creedmoor. I was hoping it would perform with 140 grain pills. Guess I'll try it out in my 223 Ackley and heavy bullets and 22-250 with 60 grain pills.

[CFJunkie]

GaCop,

IMR4166 Enduron is a IMR4064 equivalent but it is a bit slower but has the added advantage of a lot less temperature sensitivity and reducing copper fouling.
With IMR4166 in a 24-inch barrel Savage 6.5mm Creedmoor with 140 gr Hornady #26331 at 2.810 O.A.L. and 1.910 trim length with a 38.2 grain charge, you can expect to around 2665 fps muzzle velocity at about 56,217 psi.
With IMR 4064 with the same rifle and loading settings with a charge of 37.2 grains, you would get around 2664 fps mv at 55,566 psi.
So IMR4166 requires about 1 grain more than IMR4064 to get the same mv but generates a slightly higher chamber pressure.
You might use the IMR4064 load data, start with a light load and adjust it up a grain, then work up until you find a good load or see some pressure signs.

Realizing that I didn't get great results with IMR4064 with my 6.5mm Creedmoor rifles, I didn't experiment extensively with it in my 6.5s
I have used IMR4451 Enduron (a IMR 4350 equivalent) in my two 6.5mm Creedmoor Savages with great success.
In one rifle, INR4451 is the most accurate overall, beating out the IMR4350.
In the other, it is a close second to IMR4350.
IMR4451 is less temperature sensitive than IMR4350 and reduces copper fouling and, for me, after shooting over 2100 rounds with it in my first 6.5mm CM rifle and 510 rounds in the newer rifle, it has been a great 6.5mm CM powder.