IMR4166 for .308 Information

[Ryan0714]

Hello All,

Just joined in order to make the first post about IMR 4166. I looked allover the internet only to come up with zero data about this powder when I was trying to come up with a good load. Since I have tried it out I figured I would share some information in order to hopefully help some people out. Here is what I have found to be the best for my rifle. This is using a 24" Varmint barrel with a 1/10 twist.

Federal Brass
175gr Sierra Match Kings BTHP
CCI #200 Primers
41.7gr 4166
Trimmed Case Length 2.005"
2.8" COL

This is what I found to work the best for me. I do not use a benchrest sled because I believe it is cheating and should not be used. I want the accuracy to be consistent off my shoulder not on a sled. With this load I can average 0.5" groups at 100yrds using a fixed 10x scope. I have got some groups that were a little less and also a little more but half inch seems to be the average. Some of this is due to me still getting used to my new trigger, so hopefully the average will drop slightly. I am not one of those people who "claims" something they can not prove or back up. I do have the targets which I may upload later with more time. As I said from a sled it might average under half inch, but this is from my shoulder while shooting prone off a bipod and rear bag. Hope this information may point some in the right direction.

 

[swadiver]

one of my F/TR .308's did these groups with 175 SMK's on top of either 41.0 or 41.8 of IMR 4166. shot off the bench with an SEB Joy-Pod bipod and a rear rest. 5 shot groups @100 yds. good powder for the .308

 

[Brians356]

FWIW Hodgdon.com shows this IMR 4166 with 175-gr Sierra HPBT (24-in barrel, COAL 2.800"):

Strt_: 38.9 gr; 2416 fps; 48,100 psi
Max_: 43.1 gr; 2652 fps; 60,100 psi **

** Compressed
-

 

[Ryan0714]

Yes sir' that is the type of groups I am getting as well. Seems like there is a sweet spot right around 41.6-41.8 with this powder. Just glad to get some information out there so others can find it.

 

[Shynloco]

Ryan0714,
First off, welcome aboard. Hopefully this site can help you along with some of the questions you may have. Looks like your load is working nicely in your particular rifle. And since you are new, I am not sure what you mean when you use the term "sled"? If you mean a "rest" or something similar that we use to shoot off of and in recognized in international competition, that is NOT cheating as everyone shooting on the line uses one for shooting score. Not sure what position you shot that sample target from, but there are rules in competition that everyone must follow as well as to qualify the rifle they are using. Certainly there are rules governing the equipment that may be used is a specific discipline of shooting which simply means varying disciplines have different equipment and are governed by different rules. But even in load development, most use some form of a rest, whether it be a bipod or a convention rest. I use a one piece rest in load development, however that rest cannot be used in Benchrest competition, except for Rimfire Competition. In Benchrest (which many on this site shoot) competition a Front Rest and rear Bag are used when shooting for score and that can be shot from either a seated or prone position, depending on the discipline being shot. Info only.

Alex

 

[Ryan0714]

Ryan0714,
First off, welcome aboard. Hopefully this site can help you along with some of the questions you may have. Looks like your load is working nicely in your particular rifle. And since you are new, I am not sure what you mean when you use the term "sled"? If you mean a "rest" or something similar that we use to shoot off of and in recognized in international competition, that is NOT cheating as everyone shooting on the line uses one for shooting score. Not sure what position you shot that sample target from, but there are rules in competition that everyone must follow as well as to qualify the rifle they are using. Certainly there are rules governing the equipment that may be used is a specific discipline of shooting which simply means varying disciplines have different equipment and are governed by different rules. But even in load development, most use some form of a rest, whether it be a bipod or a convention rest. I use a one piece rest in load development, however that rest cannot be used in Benchrest competition, except for Rimfire Competition. In Benchrest (which many on this site shoot) competition a Front Rest and rear Bag are used when shooting for score and that can be shot from either a seated or prone position, depending on the discipline being shot. Info only.

Alex

Thanks for the welcome, but the picture above is not mine that is the other poster's. However I am getting the same results. much less fouling as well. and it does appear to truly be insensitive to the temp outside.

As for the "cheating" part what i mean is i want the load to be developed off of my shoulder and shoot with me, not from a once piece rest that holds it for you. Personal bias towards those things. Someone can claim to shoot .25"-.5" groups all day but are they doing it in a rest or are they actually shooting from their shoulder. Seen it to many times where these claims turn out to be much greater when not using a one piece rest (sled).

As I said just a personal bias, and the way I was taught. now using a bipod and a rear bag is perfectly fine by me because the rifle is up against your shoulder, not sitting in a vice. Cheers!

 

[Jackal2016]

I think the OP (Ryan) was thinking of the Lead Sleds like this when he referred to a "sled".