Help me rescope and reload for Christensen Arms Summit Ti.

[danmayland]

Here's a quick video I just made showing a few reloading tips to help reduce extreme spread (ES) in your velocity and reducing runout. Both of course will tighten up those groups!!

2 Reloading tips for better accuracy - YouTube


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[HellsCanyon]

Good tips Dan. Runout also goes a long way with have properly sized and concentric necks and proper bearing surface support inside the case neck.

This leads me to mention bushing dies vs non bushing dies. I've loaded about 5k rounds through my old Redding non bushing 280AI dies. Never had one not shoot but ES has always been mid 20's. But about a year ago I started playing with neck tension and new bushing sizing die. I found that a fired case had a .314 diameter neck OD. Perfectly concentric. I can spin the case neck inside my caliper jaws and never have it move. Once sized through my old sizing die, I noticed that case necks were ALWAYS coming out oblong. .309-.311 showing while spinning case neck inside my caliper jaws . I've since gone to the Redding type S bushing and case necks are coming out perfectly concentric and my groups and ES have reflected it. I've gone to bushing dies with all my other calibers as well.

Just something to think about!

Mike


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[robby denning]

When writing down my measurements to keep track of things I differentiate between the two as COAL = cartridge over all length and BTO = base to ogive.

Just my 2 cents and worth the price charged.

good idea

 

[danmayland]

I agree with Mike. I primarily use bushing dies with the exception being my 6.5 Grendel. I use the Hornady Custom Match Grade bushing dies with the Micro seater and have found them to be exceptionally good for runnout and concentricity.

I really like the price of these dies and I also really like the bullet collet that holds the bullet in place. You can see it as shown in the picture below:

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[robby denning]

Got home from work and hit the reloading bench.
It was a breeze setting the Base to Ogive (BTO, as suggested by maninthemaze) distance and it is indeed much more repeatable than measuring COAL off the tip. In 18 rounds it never varied more than 0.001. Could never get that close before.

I loaded the Berger 140 gr. Classic Hunter with both R26 and H4831 SC as suggested in this thread. I'm from 2 and 1 grains under max and at max for both powders 66,67,68 and 63,64,65 grains respectively (from Berger Manual).

Also tested the Xtreme Hardcore Gear Funnel.

These caliber specific funnels are great additions to the bench. They don't clog, drain fast, and have enough heft to stay on the case compared to plastic. Here's a short video demo:
[video=youtube_share;G9UenM4JVAk]https://youtu.be/G9UenM4JVAk[/video]
Xtreme Hardcore Funnel - YouTube

Time for the range


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[danmayland]

Good luck!!


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[robby denning]

Back from the shooting range. 30 to 36°, light winds, and cloudy – perfect for the chronograph.

This gun is shooting better than ever, with three groups at 1” or less. I’ve had it for three seasons and several of today’s groups are better than anything I’ve ever shot. With all the change to bullet, powder, and BTO, it’s hard to say what’s making the difference, but she’s a shooter for a light weight magnum.

Keep in mind this is a 7 1/2 pound gun which is very hard to steady, and I’m not using a lead sled, just my shoulder and beanbags—and 10x max

I don’t have my journal in front of me, but the velocities are incredible with these two powders. I had one group at over 3400 ft./s. Well over published velocities from Berger. I’ll post the velocities later, but here are all the groups I shot today. I could not shoot the 65 grain in the H4831SC as the pressures were getting too high, so five groups total

I’ll be going with either the 63gr. H4831SC or the 67 gr. R26

Several of you guys suggested those powders, and I’m very impressed with their velocities/accuracy. Thanks for all your help you guys, I’m even more excited about this. Super glad I learned to do the BTO, as it’s really nice to know the uniformity of your cartridges and then see these groups.

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[maninthemaze]

Nice shooting. It's definitely harder to shoot a lightweight rifle consistently.

I'm guessing the velocity of the R26 was more than the 4831sc. My 7wsm could push 168 berger's pretty fast. One thing to remember about choosing powders is the temperature stability. R26 is not a temp stable powder. You might not want to shoot far enough to notice the difference.

Either way.... Good shooting.

Just my 2 cents and worth the price charged.

 

[robby denning]

Thank you and good to know about the temp stable issue with R26. And yes, it was the highest velocity. I’ll post all of them when I have my shooting journal.


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[HellsCanyon]

Very cool! I walk through this whole process with a lot of my customers, glad to see you finding some success! I'd go with 4831sc. It's a touch slower than RL22 but you're throat will last longer and it's much more temp stable than RL22

*EDIT* disregard most of this post, thought we were talking RL22 not RL26.

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[N2TRKYS]

I couldn't get nowhere near the speed listed when I use H4831SC in any of my cartridges. RL26 has proven to be the ticket in a lot of my cartridges. I've shot RL26 at 30 degrees and 90 degrees and haven't seen anymore velocity change with it than with H4831SC.

Good luck with whichever one you choose.

 

[robby denning]

Here are the average 3-shot chrono velocities/Extreme Spread & Standard Deviation in order of the pics posted of the groups on page 11 along with Bergers predicted numbers.

H4831SC:
Berger says 2931-3075fps w/ 62-65 gr.
Mine-
63 gr 3127 ES 30.8, SD 15.9/ 0.6” group

64 gr 3225 ES 21.5, SD 11.2/ 1.0” group
* bolt got really sticky, primer crater/boltface marks on case, so I didnt shoot the 65 gr

R26:
Berger says 3034-3184fps w/65-68.2 gr.
Mine-
66 gr 3321 ES 4.6, SD 2.0/ 1.25” group

67 gr 3357 ES 25.2, SD 12.6/ 0.8” group

68 gr 3414 ES 20.2, SD 10.2/ 0.7”
*bolt got sticky, primer cratering


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[robby denning]

Decades of shooting I never remember getting published velocities that much higher than the manual, while still being accurate.

My dilemma now is do I worry about the temp stability with that R26 and enjoy over 3300fps with the 67 gr, or over 3400 with the 68 gr? Or go with the more conservative H4831SC 63 gr’s modest 3127fps (and the best group of the day)?

When I run those velocities through the Vortex LRBC, I expect a significant difference between the R26 trajectory/energy versus the H4831SC.

N2Turkeys makes a good case for temp stability, but I sometimes hunt well below zero weather.

I trust Mikes opinion on the H4831SC though, too!

No matter what we settle on, we handily beat the performance of my previous load: the Berger 130 gr Classic Hunter in front of 63.5 R19 chrono’d at 3103 ES 79, SD 39/ 0.8” groups

These are definitely first world problems...


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[N2TRKYS]

I don't blame you for being concerned with temp stability in the temps that you'll be hunting in. I'd go with whatever gives you the most confidence. I like to work up loads in February, cause that's typically our coolest weather. I figure that way I'm in the range of anything I would hunt in, at least, around here.

These are hunting rifles only and I don't shoot them during the summer(hot as hell here then). Lol

 

[HOT ROD]

From the looks of the two 4831sc groups. Ur rifle really like that powder bullet combo... How many groups have U shot. Will it do it again? Just my thoughts any way...

 

[N2TRKYS]

Another thing that I've noticed with my data and other's data is that low ES/SD don't always translate to the smallest groups.

 

[robby denning]

HOT ROD, I’ve only shot the groups you see but being that I’m so far behind on this project I’m just gonna trust those groups and load for them, I’m running out of range time.

I always note the sight picture just as the gun goes off and I’m pretty sure I was doing my job; if the standard deviation is high they might blow up a little bit but I’m really only looking for an inch or less and I think they’ll stay within that.

N2Turkeys I have noted exactly the same thing on ES, SD. It does not always predict your group size. That one load above was in the single digits, yet the group size was not my smallest. If I had more time I might shoot that once more just to see, but as I said above I’m running out of time

Thanks guys


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[HOT ROD]

Fair enough Robby...

 

[HellsCanyon]

(My previous comment regarding temp sensitivity of the reloader powder was directed at RL22 (I thought that's what I'd read for the loads). RL26 is a different animal and should be very STABLE for temp swings!
If you had more time, I'd run that lowest ES RL26 all day long. You can tune the seating depth to get it to shoot better I guarantee.

But if you're out of time, run the 4831 load that shot the best and make sure you have a good zero and verified velocity. Play with RL26 after this season.

Mike


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[PathFinder]

One three shot group is not sufficient data to fully understand the accuracy of a load. A ten shot group will show what's really going on. I'd shoot a 10 shot group of each of your prospect loads at 300 yards. That will eliminate any doubt about what's really going to happen. I'm willing to bet the low SD loads run circles around the others. Too many times I've shot fluke 3 shot groups only to find later that they weren't what they appear to be initially. Since I started working up over a chronograph I haven't had that issue. I still sometimes find loads with very low SD that shoot poorly but combining the two methods and shooting ten shot groups is the best method to truly understand what the load will do. Anything less is a guess.

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