I need a better method of developing loads for new 6XC

[jeffreybehr]

I’ve been reloading for about 60 years and in some respects have learned a lot but in other respects it seems I’ve learned little.. I have a 6mm precision rifle for which I couldn’t find a satisfactory sub-MOA load after 450+ rounds, and I’m about to start development with a new barrel; see...

My third reloading story, this time in caliber 6XC

This started as a 6mm Creedmoor story, or rather the rifle started as a 6Creed, but I'll start from the beginning. A month or so ago, I bought a new Savage 110 Elite Precision rifle in 6 Creedmoor.. Try as I might, after 450 rounds and at least a half-dozen different bullets, this week I gave...

forum.accurateshooter.com

So here’s my opportunity to learn to do it right (or at least ‘betterly’), as guided by some of you far-more-skillful shootists.. In this case, I’m looking for a long-range load for a long-barreled (28") 6XC (with 7" twist) that will produce no-larger-than half-MOA groups.

I have powders allegedly appropriate to the 6XC–Reloder-17 and -19, Hodgdon SUPERformance, and Win. StaBALL 6.5.. Bullets include Berger VLD115s, Barnes MatchBurner112s, Sierra MatchKing110s, Berger LRHT109s and BTT108s and Hybrid105s, Barnes MB105s, and Nosler RDF105s, among a few others.. Cases are new and used SP Petersons, primers are CCI 41s..

My normal method (sometimes NOT successful, hence this note) would be to select perhaps-three bullets and one powder and load and shoot ‘pressure strings’, that is, maybe five loads of 10 rounds each with gradually increasing (in 1- and then 1/2-grain increments) powder charges, shot in two-each 5-shot groups at 100 yards from a solid bench.. Cartridge length is determined, generally and at this stage, by what fits in the magazine.. I then concentrate on a powder-charge range based on smallest groups and load and shoot perhaps four groups in 0.2-grain increments until I find something that shoots small, or I reject this combination because none did.. At this point I usually add a different bullet to the candidates.. I keep repeating this until I find good candidates to refine.. This is how I consumed more than 450 rounds with my 30-inch-barreled 6XC, and with uncounted rounds thru the rifle’s original 6CM barrel, with no ultimate success.

I already plan to do a few things differently–I have David Tubb resizing and seating dies on the way. Also a modified 6XC case for my Hornady L-n-L O.A.L Gauge, and I’ll measure throat-land dimensions for these and other candidate bullets.. I’ve been using a NF 12-42X56 competition scope from my safe-queen 1000-yard-BR rifle(1) and will start using a Trijicon 4.5-30X56 scope on this rifle.. I’ve been using an expensive Warne Arca-type tripod but have a Caldwell FIRE CONTROL front rest(2) coming, and I already have a newish Protector Dr. rear bag.

Personally, I’m 77 years old and, with a replaced right-shoulder joint that has broken and will be replaced this summer, am very recoil-sensitive(3).. Of course my eyes are getting gradually worse but can still be corrected to 20-20.. One weekend the summer of 2007 I shot, at a thousand yards, a 4-9/16" 5-shot and a 7-odd-inch 10-shot group, so at least once I was a fairly good long-range shootist.

So, the question–how would YOU begin your load development?
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(1) The 30" barrel previously mentioned was borrowed from this rifle.
(2) Yes, I understand that this is NOT a one-fifth-the-price Farley $1000-front rest, but I’m confident it’ll be lots better than that shaky bipod.
(3) which is why I shoot a heavy rifle with a lowish-recoil cartridge and use a thick, energy-absorbing pad between the recoil pad and my shoulder.

 

[6ShotsOr5?]

I think 1.0 grain and then 0.5 grain steps are too big for loads around 40 grains total. If you’re weighing your charges—which you should be to get consistent 0.5 MOA groups—then I would start with 0.2 grain steps, and you can fine tune with 0.1 grain steps after you determine your seating depth.

 

[Jager]

I expect most of us have shot out a barrel or two, while searching for the elusive magic load.

You've got some nice gear there, so it sounds like equipment isn't the big constraint. But there's a lot to unpack in what you said. You're changing up your shooting support system, so my first question would be around that... are you able to reliably and consistently extract the group potential of your loads and get them on paper? Until and unless you can do that, nothing else much matters.

Beyond that, I agree with Delbert... I'd go with smaller grain increments.

I'd also concentrate on one bullet and one powder.

Are you chronographing your loads? Chrono stats can be a powerful tool for accelerating load development.

Good luck with everything... including the shoulder and eyes. Will be following your project with interest.

 

[Walt Krafft]

I am a sling shooter and have been shooting the 6XC in my T2K since 2003. My 600 yard load through close to a dozen barrels has been 38.0 H4350 under a 105, 107, 108, 115 grain Berger or Sierra. Always has had the potential to clean the 600 yard target with high X counts. Built a F-class rifle for a customer. We went to a match and using my ammo in his first match he shot a 197-12x on the 600 yard f-class target. I suggest you start with my load and experiment with seating depth first, and then vary the charge up and down a grain in 0.2 grain steps. The 6XC is very easy to get to shoot well.

 

[6ShotsOr5?]

I am a sling shooter and have been shooting the 6XC in my T2K since 2003. My 600 yard load through close to a dozen barrels has been 38.0 H4350 under a 105, 107, 108, 115 grain Berger or Sierra. Always has had the potential to clean the 600 yard target with high X counts. Built a F-class rifle for a customer. We went to a match and using my ammo in his first match he shot a 197-12x on the 600 yard f-class target. I suggest you start with my load and experiment with seating depth first, and then vary the charge up and down a grain in 0.2 grain steps. The 6XC is very easy to get to shoot well.

Sounds good to me that’s my 6 Creed load, and those two cartridges are very similar. Only problem might be the OP didn’t say that he has any H4350.

 

[Eloudamy]

First, you have such a humble approach. I expect you may way more about reloading and shooting than eluded in your post.

But along the way, I too have had some “wins” and a coupe years ago I decided to share some of that with others pursuing long range precision.
Here is a link to an article I authored and which was published on the LRH site. Don’t be misled by the title because there’s an approach detailed therein that has worked for me. It’s not the only way, for sure but I think I’ve experienced the same frustration I hear in your text. Take a look and see if it might help

https://www.longrangehunting.com/articles/load-development-at-home-and-in-the-field.1204/

Wade.

 

[jeffreybehr]

I thank each of you fine fellows for your input.. To answer a few questions--
1. Yes I use a chrono, a Labradar.
2. Yes I have an electronic powder dispenser, a Hornady Lock-n-Load Pro.. I have devised a method of easily checking calibration while reloading, and I check the actual dropped weight that's hiding behind the shot #, trickling to 'zero'.
3. Yes I'm actively improving my stability while shooting,
4. I was 'afraid' someone would mention the importance of case prep, something I did decades ago but not lately.. I know--shame on me!...and
5. I have no H4350 and don't plan to buy any, at least now.. Maybe later...

 

[JimSC]

Just my 2 cents worth but I have been using Erik Cortina's 100 yard load development for several years and half a dozen barrels now. Only had 1 barrel that refused to get .5 MOA groups at 800 since I have been using his method.

Long range load development at 100 yards.

I found this target, and I think it's a perfect example of how some people might choose the wrong load because they fell in love with a group without reading the groups properly. This target was shot with my 6.5x47 Lapua and 139 gr. Lapua Scenars with VV N550 powder. At plain sight, 38.5 gr...

forum.accurateshooter.com

 

[DR_2297]

My standard 6XC load is 38.5 grains of H4350. Shift it a tenth up or down between barrels and powder lots. Stick a 105 - 108 class bullet on top and go win stuff... the XC may be second only to the BR / Dasher family of cartridges in ease of load development.