Imr 4166

[RAMMONT]

Has anybody tried this powder in the M14/M1A .308?

[Phil McGrath]

I have the 2015 Hodgdon Annual Manual it lists IMR 4166 just a tic faster than IMR-4064. Its enduron tech so its supposed too be more environmentally friendly and temp stable. In my opinion IMR-4064 is more forgiving.

Looking at there 168 SMK load data.

IMR-4166 starts at 38.5grn for 2418 M/V @ 46,400psi and tops out @ 43.5C for 2704 M/V @ 60,900psi.
IMR-4064 starts at 41.5grn for 2518 M/V @ 43,800psi and tops out @ 45.9C for 2766 M/V @ 58,800psi.

175 SMK load data.

IMR-4166 starts 38.9grn for 2416 M/V @ 48,100psi and tops out @ 43.1grn for 2652 M/V @ 60,100psi.
IMR-4064 starts 41.5grn for 2500 M/V @ 45,200psi and tops out @ 45.6C for 2728 M/V @ 59,500psi.

But life doesn't start and stop with the 168-175's there starting load data looks promising with the 155 SMK

IMR-4166 starts 43.0grn for 2688 M/V @ 52,500psi and tops out @ 46.2C for 2856 M/V @ 60,900psi.

I'm thinking 43.5-44.0grs in a LC case would make for a nice load, that is if you rifle likes the 155 projo's.

[RAMMONT]

I'm getting some nice results at 100 yards with 43gr of IMR 4166 under a Barnes 168gr TTSX bullet in a Lapua case and an F210M primer (COAL approx. 2.82", COGL 2.093"). In my Loaded model M1A I'm getting under 1 MOA 5 round groups from a bench with bipod and monopod and soft pads under each.

[Phil McGrath]

I forgot too mention that another benefit of this newer powder is that its supposed too have some anti coppering agents.. I don't know how much of or if any copper shows in your barrel after X number of rounds but did you by chance notice any less after your last shooting session? What was the M/V checking in at with the Barnes.

[RAMMONT]

I haven't had time to really test any change in copper fouling, I've only cleaned the barrel once but it seemed like it took less patches and less time to get the copper out. The average muzzle velocity (corrected for the chronograph being 15 feet from the muzzle) was 2573 fps. When I worked a load up for this same bullet using IMR 3031 I got my best groups when the muzzle velocity was 2568 fps. I really want to see how the summer heat effects the speed, our average temps here have been around 20 degrees F and the summer will probably be somewhere around 93 degrees on the average.

[Phil McGrath]

John Barsness who wrote the article for Hogdgon manual is also in Montana, said he froze 223, 303brit and 45/70 overnight and kept them in a cooler with some gel packs. I guess his trip too the range is pretty short 10min or less anyway he stated that the .223 and the 45/70 picked up a few FPS. Not very scientific and he didn't state how deep the freeze was 0* or 32* only overnight but he did admit and say the rifles he used at the time of the test were cool and not cold. I think what gain he had was within the margin of era, we know that the same load on different days can give different readings even at the same temp... There being one of the new extreme powders I wouldn't expect a wide swing in velocity but you never know.

[RAMMONT]

I found an article online that is about a temperature test done on some of the Enduron powders, they actually include temperature data from 43 degrees to 97 degrees.

http://www.ammoland.com/2015/06/imr-...#axzz3vvZCWo8T

[RAMMONT]

Well I finally setup a 200 yard steel plate on my range and I did a little more testing with the powder. I got fantastic results with 43gr of IMR 4166 under a 168gr Barnes TTSX BT (#30878) and primed with a F210M primer. COAL was 2.83" and COGL was 2.093". Case TTL was 2.006". Case headspace was 1.628". The cases were twice fired Lapua and I annealed the necks before I sized them. I fired the rounds from my Loaded Model M1A with a JAE G3 stock, a Vortex Razor HD scope, a bipod with a carpet under it and a monopod on the rear with a small rubber mat under it. I was sitting at a bench.

I fired at 100 yards and 200 yards, the 100 yard target was a Briarbank target and the the 200 yard target was a 4 inch AR500 round plate. Both were 5 shots. The average of both groups was 0.83 MOA. I'm in no way saying that this will happen all the time but I'm pretty darn impressed with how things turned out. Now I want to see if I can get it to work in my SOCOM.

[Phil McGrath]

Nice shooting and nice groups, looks like its going too work well.

[m14brian]

That is nice work, Rick!
m14brian

[RAMMONT]

Thanks, I need to do some more testing to see what kind of fouling I'm getting, so far it looks like I'm seeing less copper and carbon. I seem to be seeing less carbon but it cleans out so fast that the first few patches come out very heavily fouled and black. The brass itself shows far less carbon on the necks, usually my cases seal very well and get a lot of carbon on the case forward of where the brass obturates to the chamber wall (obturation is usually somewhere along the shoulder). With 4166 I'm getting very little or no carbon anywhere on the case. I have a borescope and I do see copper in the bore but mostly toward the muzzle, none at the chamber end of the lands and it seems to take far less to remove what little copper there is.

[m14brian]

Would that be because of the chemical makeup of the powder, or the shape of the grains? Could they add in compounds that burn the carbon? Please forgive me, I'm a super newbie to reloading.
m14brian

[RAMMONT]

I'm pretty sure that it's just the chemical composition and any coating that they use.

[Phil McGrath]

Not knowing how many rounds Rammont fired or how fouled his bore gets after X amount of rounds fired, I was wondering if he had seen any of the effects pos/neg yet..

[RAMMONT]

The current cleaning was after firing 23 rounds since the last cleaning. From this point forward, I indent to just remove the carbon after shooting it and then seeing how many rounds it takes before I see the groups worsen and taking note of the relative amount of copper that I see.