Home Forums Reloading Big Game Rifles Ladder step....... for seating depth?

Here's that article about Berger bullets.

https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

The only condition I would add is that any bullet that is asked to jump a large distance to the rifling better have the chamber as concentric and parallel to the centerline of the bore as is possible.

Just read it- VERY interesting. I remember someone posting here a while back that he discovered seating depth had a greater impact than powder charge. We should have made a sticky out of that post.

I got some new bullets coming this week!!!

Timk - you get to shoot yet?

Ammo is loaded, hoping to get out tomorrow.

So another question regarding this. Real World. What IF.......you have to begin your loads at magazine length rather than "off the lands"?

You can go shorter from there.

I guess I will give it a try until I get to factory spec length. Thanks Mathman.

Lately I've been playing with a rifle that likes them seated shorter. I just had to test it to find out.

Latest test. This is on a .224 Valkyrie. Shortest is 0.010" below mag length (2.250"). Longest is 0.030" longer than mag length. My mags will allow me to go longer if desired, but it sure appears to like a little more jump.

The dimensions on the targets correspond to the direct reading off the caliper using a bullet comparator. Hence the confusion. All shot indoors at 100Y. I got good breaks on all but one shot that went off a touch early.

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

In my experience, chasing the lands is overrated, at least in typical hunting and varmint rifles.

A lot of my precision rifle shooting is with the AR15 platform these days, so cartridge length is generally limited to 2.310" or shorter. In several cases with the most accurate setups, I've found best accuracy at much shorter overall length, like 2.235", despite that being .050"-.100" off the lands, or more. Other times close to the lands does work best, but it's definitely not a hard rule or even common enough to bet money on.

For my purposes, I start with the shorter of either mag length or max length to the lands. In many cases, that means going with mag length or shorter, which generally is no handicap if you're willing to experiment. Don't hesitate to go significantly shorter than mag length; I like to test to at least .100" shorter if possible. Jumping in increments of .030" works to get started, then fine tune in smaller increments depending how much care you want to put into loading. With a lot of bullets and applications, it seems to me that it's not worth chasing anything finer than about .010".

You know- I guess this is beginning to explain accurate Weatherby's.

Getting excited to shoot again here !

Tim K - I did the math and your best load is .04 deeper which is the increment suggested in the Berger article. Cool stuff. I had a dozen or so already loaded with a standard load and last night i shrank 3 by .04 and the final 3 by an additional .04. Going to do the same for my 6mm. Wish I had my own range and means to more easily shoot and test.

Once I find sweet spot COAL I can tinker a bit more with the powder charges.

Man- I used a comparator to measure from Ogive on the Sierra's then loaded some Speers and the differences were pronounced. Gonna go blast through what I got but...will probably be scratching my head when I am done. No idea how far off the lands I am because I stated at mag length. Sigh.

Just returned from the range :and the ringing out my initial less than perfect control group testing.

6mm REM: meh
I never had a 'great' load for the 105 grain Speers in my 6mm so I dug up a pet load with same powder from another guy who said it worked in several rifles. His was one grain more than mine and getting close to max so I thought it might be worth a try on these heavy bullets based on comments byu some folks here.

My standard load length worked best and it was the longest COAL. Was rather hoping a shorter length might surprise me. I am thinking I may just stick with 100 Sierra - or maybe some Gamechangers.

On to my 260 REM:
No surprise that my old formula for 120 Sierras shoot well. Like the 6mm this was the longest COAL and I worked down from this length.
Next load .04 shorter - not so great.
going shorter another .04 - worse.

At this point I was thinking conventional practice of loading as long as possible seemed a good rule but I still had my shortest COAL to try
Shot last loads - .04 shorter still
AND......BOOM- awesome. One ragged string.

This is great news as it means more mag space. So, if I want to migrate off the Sierra's and go to the Gold Dots I just bought I have the ogive length and will match that as close as possible and load with same powder weight.,


Should work- right?

Fun stuff- beats Carona-ing around all day !!!

Guys, just got back from a well planned range trip and things begin to make a lot of sense. Like.....accuracy depends mostly on the timing the bullets exit from the muzzle. Crazy or ??/


Today was nice and chilly so off I went to the range. social distancing....Ugh.

Using the .04 step I was very surprised at some of the results. Differences were every bit as much, or more, of an impact than ladder stepping powder charges.

Made Identical loads for 3 different seating depths for my 260 and my 6mm.

POI was noticeably different between depths. In both cases the #2 seating depth produced much better groups than deeper or shorter.

Longest loads produced close to 2 inch groups. Amazingly, .04 shorter gave my 260 a great clover leaf and tight slight string in my 6mm.

I did a load of other bullets but am finally committed to over simplifying, de-mystifying, and idiot proofing against myself.

From now on (or at least until l I re-stupid myself listening to others) I will be : sticking with Sierras, one powder for all three deer cartridges , using light powder loads because A) I am using Sierras and B) no need for long range shots.
One more bonus. I got a new prescription for contacts and was told my eyes had change and prior prescrip was over correcting. Man, took out the 1911 and could clearly see the sights this time ( not a fuzzy wad) and shot like I would love to always shoot! So happy.

All in all, A great day for me fellas !!!