Okay, so you wanted a seat depth test, here is one I ran yesterday. Rifle is a .223 encore with a 24" Bergara barrel. I could not get a full .120 off the lands as per the Berger website due this particular combo bottoming out my seating die about .080 off the lands. I started with the first set about .005 into the lands, second set about .025 off the lands, third set about .053 off the lands, and the last set about .072 off the lands. I had one called shot, the wind was running a little bit and bounced me right as the trigger broke, but it didn't move it too hard, and it is marked on the target. Load is 25.5 of AA2230, 55 Hornady V-Max, WW brass, Fed 205GM.

I could tell no significant difference in seating depth in this rifle, which is pretty much what I have been seeing all along. This was a last ditch effort to make this load shoot, looks like that is just as good as it is going to get which has been what my ladder tests and OCW work has shown. I will go to a 50 grain Blitzking and IMR-4198 next, I think that load may have more potential.

Thank you very much for doing the test and taking the time to post.

I too have found (like we all have) that sometimes a particular gun just won't "like" a specific bullet. You still have to find a good combo.

I don't know if you read my last test posted. I found that in my .300 WM with the max Lyman data load of H-4831 of 79 gr with the 165gr Hornady SST I couldn't get acceptable accuracy by changing the seating depth........ or even dropping the charge weight by .3 gr at a time.

I tried the test with the same bullet at 75 gr of powder and was able to tune it just fine. I bumped it to 79 gr to get better velocity. The first load chrono'd at 3050 to 3100 fps and it shot well with just the seating depth tuning. When I bumped it up and got 3200 fps, I couldn't tune it.

I tried again, but with the 165 gr Sierra at the 79 gr charge. It shot great at 3200 fps and gave a 1 3/8" group at 200 yards.

Maybe when you change bullets you will find one the gun likes and you will be able to tune a high velocity load with just seating depth like the Berger site says.

I bet you do and please keep me posted. It's interesting.

After looking at your test target, I bet you could tune that load with seating depth changes only.

On the one that you called "left" , you may have had a decent group. Further tuning by small increments in or out I think is worth a try, especially if you really like that bullet and want to shoot it for some reason.

You're talking about the load that was about .050 off the lands, right? I saw that, and the answer is... maybe. I still think that group may have been a fluke. I am done with that bullet in the .223, my .220 swift shoots them just fine so they have a use elsewhere.

I have a ladder test loaded up using a 55 remington that I will go ahead and bump the depth down to .050 off the lands before I run the test and see where that goes. The 55 remington I seriously doubt will be a screamer, but it's main purpose in life will be something cheap for my son to practice his field shooting skills with. I got 400 of them at an estate sale for $10, so they are cheap enough.

Don't get too cold up there tonight, I see ya'll have a little snow. We do too, I am over in the TX panhandle.

JTPinTX, would you mind explaining the results? 'Groups' three and four have arrows pointing to targets five and six?

If I take the results at face value, it would seem that the best seating depth was .025 off the lands. I would take load three and shoot seven of them to see the spread.

Yeah JT, the .053" off the lands load.

I would load 3 of those, 3 that are .040" off and 3 that are .060" off and see which ones shoot the best.

If you get something that looks good but still needs help, load 3 on both sides of the charge weight you are using. You know, 3 at .3 gr less and 3 at .3 gr more.

It was cold. My furnace came on in the middle of the night a few times!

Hey 303Guy, all the arrows mean is the lower targets were my aim points. For the top groups I was actually aiming for the middle squares, and for the groups in the middle i was aiming at the bottom squares. The rifle is zeroed for a different load and shoots high with the one I was testing.

rc, we got maybe 4-5 inches here, we are in the SE corner of the TX panhandle, didn't get hit quite as hard as the rest of the folks in the panhandle.

Thanks JTPinTX. OK - I have a theory. It is this; seating depth may be a bit of a misnomer in that we refer to bullet clearance from the lands as 'seating depth'. Seating depth should be just that - the depth of the bullet in the case. Seating depth could be significant in so far as the 'dough-nut' is concerned. Also, case neck grip.
Having been doing a bit of loading today, I became aware of differences in case neck tension from case to case. Now, the deeper the bullet is seated, the less sensitive the grip becomes relative to neck length. At a smaller bullet jump, the more sensitive the load becomes to ignition consistancy. At a certain point, the jump of the bullet will give it the most consistant start in that it will be moving fast enough to overcome the drag of engraving into the rifling. Too much jump and the bullet protrudes into the case past the 'dough-nut' ring. Then of course, there is bullet alignment with the bore. Too much jump and aligment goes south.

Just a thought!

303Guy- These loads are seated deep in the case, even when they are touching the lands. It is chambered pretty short, and with bullets with a longer sleeker ogive it is really hard to get them deep enough to get off the lands. With my factory RCBS die bottomed out just shy of crimping the rounds, and with the bullet seating stem bottomed out, I was just getting about .005 off the lands with the 55 V-Max. I got around that by pulling the seating stem out of it and cutting as much as i could off of it in the lathe, allowing it to go deeper in the die and increasing the adjustment available. Just an ideosyncrasy of this barrel/die combination.

I may dredge up this thread later as I do some more tests. Wind is supposed to blow like crazy here for the next week or so, so it may be awhile yet. Will keep you guys posted.