Seating Depth Opinions

[JoeJoe]

I'll begin developing loads for a .308 pretty soon, and I've decided to start with Sierra Matchking 168gr bullets. Is there any value to measuring things up and seating bullets closer to the lands....or just stick with the 2.800" OAL listed in my manual? My rifle has a box magazine that will allow a little longer overall length (about 2.93" with a little room to spare).

Thanks!

[Robinhood]

SMK's will shoot well with a big jump. If you have to start with .020 Jump and work back from there. I think .030 was a good place for some

[6mmBR_Shooter]

I'll begin developing loads for a .308 pretty soon, and I've decided to start with Sierra Matchking 168gr bullets. Is there any value to measuring things up and seating bullets closer to the lands....or just stick with the 2.800" OAL listed in my manual? My rifle has a box magazine that will allow a little longer overall length (about 2.93" with a little room to spare).

Thanks!

Depending on your accuracy expectations, there can be a significant increase in accuracy based on seating depths. Are you plinking or competing? SMKs are generally forgiving when to comes to seating depths, but if you want to wring all the accuracy possible from your rifle and load, tweaking seating depth is a good step to do.

[JoeJoe]

No competitions for me at this point, but I am interested if I can find something relatively close to the KC area. Right now, this rifle switches between 100 yd paper punching, and sitting in the deer woods looking over some pasture land.

[Stumpkiller]

I shoot a .260 REM (same 2.800" COL as the .308 WIN) but NONE of my reloads are that short. I have just found a "happy" spot at 2.835" (0.045" jump) with the Sierra 130 gr TGK, the shortest cartridge I shoot, and my Hornady 143 gr ELD-X I seat at 2.890 (0.015" jump) which is the longest. For some reason the GameChangers preferred much more jump than I had been using with other bullets. You have top play around, it would seem.

I was going down to 0.015" jump with the TGK but my Savage seems to like a bit more run-up to the lands. My Sierra 142 gr MatchKing load is 2.854" COL with a 0.015" jump. It's all about the ogive of the bullet. Note that I am shooting 46.3 gr RL-19 with the 130 gr TGK and it is very compressed but shows no signs of excessive pressure.

The magazine in the M11 will allow 2.9"+ as you note - but you want to find out where your bullet touches the lands when in the chamber and go shorter - I use a Hornady modified case and Overall Length Gauge.

Deer season starts in three weeks and I did a "one shot" group with a clean and unfired barrel last Friday. Could not be happier with the result (and no, this is not always the case, unfortunately). I do a fouler to see how the all important first shot goes when I do a range session and usually I am happy to be in the 2" red circle. My sporter weight barrel tends to drift slightly to the left as it warms up.

https://i.imgur.com/zAH1NUd.jpg

[charlie b]

I was surprised at my 12BVSS throat. When new the 168 SMK's at 2.80 OAL were .025 from the lands (maybe even a little closer).

[Stumpkiller]

PS - With Federal Factory 142 gr Sierra MatchKing and a 2.800" COL I can consistently get 1-1/2" groups at 100 yards - and that is a hefty jump. When reloading the SAAMI stated measurement is a good place to start.

[varget204]

If you want most accurate loads,measure distance to lands and grooves,determine how far[distance] jammed or off x # of .0000, from L and G. BTO[base to ogive] what shoots the best.Measure Ogive of bullets,sort in .002 to max.003 groups Load by BTO, COAL is a reference/ a guide.OAL is Only important,will it fit magazine,NOT FOR SEATING

[Bill2905]

It's useful to know the maximum allowable base to ogive length for any bullet you plan to load for your firearm. I encountered several popular bullets which, when loaded at the OAL listed in the manual, ended up jamming into the lands in my .223 Savage barrel.

[JoeJoe]

Picked up a couple boxes of Sierra MK 168gr. Did some careful measuring, and came up with 2.830"-2.834" when bullet is touching the lands. I ended up seating to 2.81" as a starting point.

[Robinhood]

Dats what I would have done. What brass are you using?

[JoeJoe]

Hornady brass

[Texas10]

After screwing a Shilen S.M. barrel in 308 on my model 10 action, I first tried FGGM in 168 SMK and found it shot very small groups. I measured the base to ogive and found the factory load was .005 to .007 into the lands in my barrel. So that's how I loaded my first handloads using Varget and got very similar results. Later I tried .020 off and found it to be slightly inferior, again, in my barrel. Overall though, I find Sierra SMK's prefer a generous jump in my other barrels.

[JoeJoe]

Stumpkiller....what are your overall thoughts on the .260 Rem? I'm thinking about my 2nd Savage being a 12 Long Range Precision in this caliber.

[J.Baker]

Stumpkiller....what are your overall thoughts on the .260 Rem? I'm thinking about my 2nd Savage being a 12 Long Range Precision in this caliber.

6441

[JoeJoe]

Sorry......I posted a very similar question as a new thread :eek:

[charlie b]

6441

ROFLMAO love the graphic