Gastro Gnome - Eat Better Wherever

IMR 4166

Redmt

Well-known member
Joined
Feb 12, 2021
Messages
3,115
Location
San Antonio Valley California
I picked up 8# of IMR 4166 because it was available and a decent price! It claims to be a good substitute for Varget but I'm not finding much in load info in a 40gr. Varmageddon, only down to a 55gr. bullet. Can anybody suggest a starting load for the 40gr. FB bullet for the .223? While I have been reloading for quite a few years, I've never been much for experimenting outside published loads.
I'm also hoping to use it for 6.5 CM, .308 and .300 Win Mag If anyone can offer some help there also.
 
For .308 150 gr bullet use 43 to 48 gr IMR 4166. That's direct from the Hodgon website.
 
Seems that Varget or 4166, if they are that similar, would be too slow for a bullet that light in that cartridge. Varget is 4064 burn speed, which is on the border between fast and medium burn rates. In other words, it’s slow for a fast burn rate powder, and fast for a medium burn rate powder. Too bulky to get enough in the case
 
Using Hodgdon's online Reloading Data Center I find IMR 4166 listed as an appropriate powder for several 223 loads, from 50 grains bullets all the way up to 90 grain bullets. I do not see it listed for 40 grain bullets. So, I'd use it for loads listed by Hodgdon.

For your other rifles, 6.5 CM, 308, and 300 Win mag - I'd also recommend you stick with published loads.

I've been doing some loading with these newer IMR "enduron" powders and I like them, but I haven't use IMR 4166 yet.

Regards, Guy
 
In case you haven't used it before, the Hodgon online reloading data allows you to select cartridge, powder, and bullet weight and then provides various recipes in grains that yield corresponding velocity values, minimum to maximum recommended. I think Hodgon leans towards conservative on their maximums. I load IMR 4350 for my 30-06 and their maximum recommended powder charge is slightly less than what I'm seeing universally posted on various forums as the "standard."

Edit: Guy was posting the above as I wrote this. Sorry for the redundancy.
 
Last edited:
Using Hodgdon's online Reloading Data Center I find IMR 4166 listed as an appropriate powder for several 223 loads, from 50 grains bullets all the way up to 90 grain bullets. I do not see it listed for 40 grain bullets. So, I'd use it for loads listed by Hodgdon.

For your other rifles, 6.5 CM, 308, and 300 Win mag - I'd also recommend you stick with published loads.

I've been doing some loading with these newer IMR "enduron" powders and I like them, but I haven't use IMR 4166 yet.

Regards, Guy
If for example Hodgon lists data for 40 and 60 gr bullets, one should be able to mathematically extrapolate what the safe "medium" powder recipe would be for 50 gr bullet. Just stay away from maximum recipes when calculating.
 
I know you know this already but for those that don't. Direct from Hodgdon: IMR4166 "This propellant performs comparably to Hodgdon Varget but charge weights are materially different"

I haven't looked at kernel size but 4166 could have much larger kernel making the optimal load for the 40gr bullet too bulky for 223. Also, I want to say the last time I used Varget in 223 with 40 and 50gr bullets I ran out of room and needed to heavily compress the loads before hitting a published max load. This could be the issue with 4166.

I don't like to do this but in theory you could use the starting load for 4166 and the 50gr bullet and work up. You could risk wonky pressure issues with low starting loads and may find that you're not getting even close to the performance of Varget or even better Benchmark.
 
I know you know this already but for those that don't. Direct from Hodgdon: IMR4166 "This propellant performs comparably to Hodgdon Varget but charge weights are materially different"

I haven't looked at kernel size but 4166 could have much larger kernel making the optimal load for the 40gr bullet too bulky for 223. Also, I want to say the last time I used Varget in 223 with 40 and 50gr bullets I ran out of room and needed to heavily compress the loads before hitting a published max load. This could be the issue with 4166.

I don't like to do this but in theory you could use the starting load for 4166 and the 50gr bullet and work up. You could risk wonky pressure issues with low starting loads and may find that you're not getting even close to the performance of Varget or even better Benchmark.
Interesting. I notice that there is little to no room for properly seated bullets after filling my 30-06 cases with recommended charge of 4350. That powder must be getting compressed loading at the prescribed cartridge length. I have plenty of room in my Springfield's magazine box (military ammo is clearly longer) so I've been thinking about changing bullet seating height to see how that affects performance.
 
I read the "materialy different" but didnt quite get the point,,,, yep I get the part about powder A loads different capacity than powder B. Materialy different seems to go over my head, but somedays a screwdriver can be confusing. Being a card carrying senior citizen, I like to be damn sure I don't do sumthin stupid....
 
I know you know this already but for those that don't. Direct from Hodgdon: IMR4166 "This propellant performs comparably to Hodgdon Varget but charge weights are materially different"

I haven't looked at kernel size but 4166 could have much larger kernel making the optimal load for the 40gr bullet too bulky for 223. Also, I want to say the last time I used Varget in 223 with 40 and 50gr bullets I ran out of room and needed to heavily compress the loads before hitting a published max load. This could be the issue with 4166.

I don't like to do this but in theory you could use the starting load for 4166 and the 50gr bullet and work up. You could risk wonky pressure issues with low starting loads and may find that you're not getting even close to the performance of Varget or even better Benchmark.
If Hodgdon doesn't list data for the load one is interested in then it's likely not suitable for that load. They do respond if you contact them however.
 
Whose bullet are you using?
Sometimes the bullet manufacturer will list powder/bullet combos that the powder manufacturers don't.

Good example would be Alliant and the 284 Win with anything but a 110gr bullet.

I've seen where 4166 would be a good powder for 7mm-08, so may be decent for your Creedmoor & 308.
Not so sure about your 300 Win Mag.
Might be a touch fast on the burn rate.
 
I have looked at a few of the manufacturers load specs. The problem as we all know is available components. Barnes is actually my go to bullet. Unfortunately, Barnes has poor load info and I haven't seen Barnes available in either .264 or .30 calibers. I have both Barnes and GMX in limited supply. I could burn up either of them trying to zero in on a good safe load and then not have any for hunting, especially in .30 cal. where I'm loading for 3 different calibers.
 
I have looked at a few of the manufacturers load specs. The problem as we all know is available components. Barnes is actually my go to bullet. Unfortunately, Barnes has poor load info and I haven't seen Barnes available in either .264 or .30 calibers. I have both Barnes and GMX in limited supply. I could burn up either of them trying to zero in on a good safe load and then not have any for hunting, especially in .30 cal. where I'm loading for 3 different calibers.
Hammers in stock all the time. mtmuley
 
I haven't had much luck with the Hammer especially in my .300 Weatherby. I was missing the load. I couldn't get them to group satisfactorily. Honestly, it was getting too expensive to try and find an accurate load. After 60 rounds, I gave up. So did my shoulder. They certainly are the best looking bullet I've ever seen.
 
Back
Top