Author Topic: 7M-08 reloads (Read 1181 times)

longwinters · « **on:** July 03, 2003, 10:51:47 AM »

I am getting a 7M-08 barrel for my Encore. Anybody have one that can tell me what the best OAL for this caliber in this barrel would be?

BruceP · « **Reply #1 on:** July 03, 2003, 04:40:04 PM »

I know this is not what you were looking for but the answer is that you will have to wait till you get your barrel and see for yourself what it likes. First all barrels even from the same company will not give you the exact same max. OAL. then even if two of them did it does not mean that they will both shoot best with the same OAL. I ususally start just short of the lands and then with the same powder charge start seating the bullet a little deeper (about a 1/8th turn on the seating stem) and shooting groups at each stage until the groups shrink or until I feel I have gone deep enough. (about an aditional .050" from the starting point.) If that happens I then start with another powder and do it again. Most of the time I find an exceptable hunting load (1" or less) in a hunting rifle somewhere around .020 to .035 off the lands. Others may have a better way but this is how I work up a load and most of the time if I pick a powder of proper burn rate I wont have to try but 1 or 2.
BruceP

Duffy · « **Reply #2 on:** July 03, 2003, 06:21:38 PM »

Bruce gives sound advice, each bbl is different. Just for starters my factory 708 shoots best at .030 off the lands. It will shoot well closer and farther but it's just more consistant, velocity and accuracy wise at .030. I started at .010 but was getting spikes and not very good extreme spreads. At .020 things got a little better and at .040 velocity dropped off and groups were slightly erratic but not that bad. Thirty seems to be just about right. My Hornet likes .035 the best no more no less.
Also VV N550 works just super in the 7-08 15" bbl. at least in mine and the fellow that told me about it. I tried Varget, IMR 4064, 4350, AA2460(flamethrower) Ramshot TAC, H380 and the N550 beats them all. Varget would be my second choice, it gave good vel but the accuracy wasn't quite as good. It also took about 100 rounds before mine started shooting good even though I lapped and polished it, but part of that was me getting used to the gun too!
Ryan

longwinters · « **Reply #3 on:** July 05, 2003, 10:05:39 AM »

Ok, thanks for the info. My barrel will be 24". Hopefully it comes in this coming week. :grin:

Duffy · « **Reply #4 on:** July 05, 2003, 02:46:54 PM »

In your longer bbl the slower powders(ie 4350) will probably work better than in the 15". Is it a custom or factory bbl? Seems like the custom bbls shoot better right away and don't need as much break in.

PA-Joe · « **Reply #5 on:** July 07, 2003, 04:21:15 AM »

You didn't say what you were going to do with this 7mm08? Deer, Bear, Elk and at what range. I use either a 139 hornady over 35-39 grains of 4064 or a 162 over 36 grains of 4064. Pass thru's on eastern deer out to 300 yards. This is a light load but all I need for a clean hit. Use stock OAL.

longwinters · « **Reply #6 on:** July 08, 2003, 01:06:27 PM »

This Encore in 7M-08 (24") will be mostly for Whitetail. Although perhaps for antelope this Oct also. I will be torn between the 243, 7M-08 and 7MM. However, as much as I appreciate all the feedback, I am looking for what would be considered the best OAL for this specific caliber, length, Thompson Encore barrel. Thanks.

Ol` Joe · « **Reply #7 on:** July 08, 2003, 06:26:52 PM »

There is no one perfect COL. I`m on my third 708 and everyone has varied a couple thousandths or so. What has worked in mine most likely won`t work in yours.

The first thing you need to do is measure off the ogive of the bullet not the tip when setting your COL. There are a few good tools that aid in doing this. I like the Stoney Point OAL tools and Sinclair also makes a good comparitor.

The bullet you use will have a major effect on the COL, the weight, manufacture, shape (spitzer, rould nose, plastic tip, ect) even different lot runs will change it at times. This means every different style / brand bullet you load will have a different COL. Once you find the distance from the lands your rifle likes, you can use a comparitor to set any bullet you load to this lenght. Remember though that the shape of the ogive on other bullets may cause the tool to read a few .001s off so you may have to adjust up or down a bit when working with a new bullet, but you will be very close.

I`d start at a COL that is just off the rifleing in your barrel. There are no magazine constraints to consider in a Encore so the SAAMI COL of 2.80 can be ignored, start as long as possible - with out jamming the bullet in the lands and staying a min one caliber deep in the case (.284") - and seat the bullet deeper in .005" increments until you find your "sweet spot". This could be any lenght, you just have to play with it till you find it. What you are looking for is a lenght where the bullet exits the barrel in a "dead spot" in its` vibration patern giving you your best accuracy. The idea of the proper COL is to "tune " the load to your guns barrel.

Hope this helped..........

longwinters · « **Reply #8 on:** July 09, 2003, 12:39:49 PM »

Thanks Joe. Your info was very helpful. Now if I can muster the patience to reload all of those different lengths until I find the best one. Also, I am proud to be your 1st response to a post here. Welcome!!!

BruceP · « **Reply #9 on:** July 09, 2003, 04:22:50 PM »

Longwinters, Joe went into a lot more and better detail on finding the OAL for your rifle. Good job Joe and welcome. I might add that to cut down on loading and keeping seperate all the different lengths, what I have done is buy the very inexpensive Lee Hand Press and take it to the range with me. I load all of my loads to the longest length at my bench and take them to the range. I fire a group (three shots) as loaded. Then with my seating die in the hand press I seat three rounds aprox. .005" deeper and fire them, and so on till I find the best length. Just dont load the rounds way ahead of time. I have found that If a compressed load sets for a long time and you try this some rounds once the bullet is set back wont have the neck tension to hold the bullet and it can be pushed back out to an OAL longer than you started with. I have only had this happen with two or three rounds but it has happened. Also once the best OAL is found seat the remaining loads to this length at the range and be sure to save a few and take them home and use them to reset the seating die in your bench mounted press. Having to reset the die from one press to another is the only downside to this.
BruceP