Updated with 2nd round results - Began new load development today for the 6.5CM

thor447

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Let me start off by saying, I realize this thread is useless without pics! I know, I'm sorry!

I got some new Lapua brass and was planning on doing a new full top to bottom load development on the 6.5 Creedmoor. It's always been a pain in the rear for me because I have to travel about 45 minutes out to Lexington to be able to shoot it at least 100 yards, so in the past I'd always take multiple trips when trying out different powder charges or seating depths. I decided to make my experience somewhat easier this go round and I bought a Lee hand press. My thought was when I was testing different seating depths, I'd just load all of my ammo long, and take the equipment to the range and seat the bullets to length there, giving me much more flexibility and the ability to load additional sets to validate results.

First off, let me say that any fears I had about any slop in the breech lock bushing of the Lee hand press were for nothing. There is zero play in it when tightened down and I was able to seat bullets with fantastic consistency with my Redding micrometer die.

I loaded everything (very) long at home, and the first seating depth length I was going to test was loading the rounds to max mag length, in my case it was 2.176 CBTO with the 150gr SMK's. In the past, the best load I could find was well over mag length which stuck me with a single shot rifle when using those 150gr SMK's. I was hoping to find something comparable in the mag length or under range. I loaded up 8 at 2.176, used three to foul the bore a little bit, and shot a 5 shot group with the 2.176, which (according to my notebook) grouped at 0.55" at 100 yards. Pretty darn good for my sloppy shooting! I started seating shorter in four shot groups, all the way down to 2.136. As luck, or irony, would have it, every single group of four shots was worse than my first group of 5 shots at max mag length. I then loaded another 10 rounds at 2.176 and did a full 10 shot group which measured 0.64".

All of this was just using a middle of the road powder charge of H4350. I did not bring a chrono on this trip. Next weekend, I'm going to head out there and will do some powder charge testing with everything loaded to 2.176.

Normally I'd always developed a load with charge first, then seating depth. Another member on here mentioned that they did it with the seating depth first, then the charge. I looked elsewhere online and found that it was a hotly debated topic, but several people prefer the seating depth first, so I thought I'd give it a try this go round. I just found it funny that the first seating depth I tested was far and away better than anything else that was tested today.

Next weekend I'll have some chrono results, and will upload pics as well.
 

swampratt

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Wow, thanks for the write up.
I have found seating depth makes a huge difference.
You just found that out also.
Man it was nice you had the opportunity to try another 10 rounds at the same seating depth as the first good grouping rounds you hade.

Kind of eliminates any thought of the gun being fouled or different temp or shooter error.

Excellent.
 

thor447

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In my case there will always be some shooter error involved. I swear I could strap that gun down to a concrete bench and still find a way to push one to the right! But yeah, I always knew seating depth was a major factor, but I always tested it after settling in on a charge weight. This time was different, but I am pleased with the results thus far. I know that I'll be taking that hand press to the range for a few more rifles I need to develop loads for. I can't believe it's taken me this long to spend the $50 to get one. What a handy little tool. I was worried that to keep the consistency I wanted, I'd have to bring an arbor press and an inline seating die, like a Wilson. That little Lee did a great job, but I was also using a very good Redding die.
 

swampratt

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You can take a stiff piece of plywood about 12" wide and as tall as a table top and screw a 2x4 to the top of it.
Mount your regular press to that and lean it up against a table or chair or wall and use it.

I took it a bit farther and made 2 outriggers about 1/2 as tall as the plywood and hinged them to the plywood.
I can now have a free standing press.
Fits in the seat of a vehicle like a passenger.
 

diggler1833

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I'm a seating depth first guy, and it has always worked out for me...but there is no harm in doing it the other way.

The charge weight fist guys often look for velocity flat spots, and the seating depth guys look for accuracy nodes across depth windows (barrel erosion...why bother chasing the lands?).

Anyway, unless you're interested in benchrest or F-class shooting, I typically make gross depth changes of .015-.040 depending on how long my throat is.

A good example of why I play with seating depth first is with my latest "salvage" Savage 110 Timberline. The throat is extremely short, and I'm into the lands immediately.

Here are the first two quick groups with 129gr Hornady Interlocks just to get things going. Bear in mind that this bullet has a secant ogive and is a bit more depth sensitive (ignore the CBS on the middle, the groups are top and bottom).

20210812_110506.jpg


Since three shot groups are not as reliable, I tried the same test again, before loading powder charges in 4-shot groups and going from there. Second target from left is the 2.665 COL, just to make sure it was wild...and it was. The next groups were all at 2.680. For reference, 2.690 puts me into the lands, so I'm only jumping. 010 here.

20210816_200838.jpg


I'll probably experiment with higher charges of this combo, but my hunting bullet for this gun so far is the 120gr Nosler BT, which has thrown several groups in the .4s during development., and produced a 1.5" group at 300 yards.

Seating depth matters as much or more than charge weight.
 
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PBramble

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There is so much that has become contested these days it's hard to decipher it all honestly. Statisticians have said that looking for flat spots in your velocity is an impossibility as there is not enough data from 5 shot groups. Others will tell you there are no flat spots and if you repeat your testing on another day you will see different "nodes". One of the best shooters in the US has said he picks a speed, works up to it and then adjusts seating depth.
 

rockchalk06

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SMK's fly great out of my Bergara, but I found the Berger and Hornady's did a tad better.

Last year was the first year I didn't worry about the group when developing a load. I shot everything over a chrono and worked on seating depth with a middle of the road charge. Focused on the standard deviation. Then once I was below 10, I worked on charge and printed/ recorded everything.

I would have some groups at a certain depth that might print Sub 1/2 MOA, but have an SD of like 25. Then have one that printed 1/2 MOA with an SD of 5. Those Itty bitty SD's were my area of focus.

It was a fun experience, well until my throat erodes and I have to work on setting depth again.
 

Jcann

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I generally push to find max or near max velocity while watching pressure to take as much advantage of the bullets BC as possible. After finding a velocity node (this could be as wide as +/-50 FPS) which yields consistent POI I move to seating depth changes to tighten group POI.

Next I run this recipe out to distance. I shoot an 8” steel plate from 200-949 yards (max distance on the farm). I’m not necessarily looking for group size for a hunting load but rather consistency. Do I observe my groups, yes, I like to pat myself on the back too but if I’m shooting inside an 8” plate out to distance I feel confident when the time comes to do it on a live target. It’s not uncommon to shoot 200 rounds of 7WSM in a day gathering information and filling out my data book.

What I’ve found to be consistent with my rifle when shooting 180 grain Berger hunting VLD’s is a velocity between 2950-2975fps with a kiss to the lands. In fact, this is so consistent I no longer mess with verifying it at distance…I just load it and shoot it.

I think one common mistake many make is not settling on a specific bullet Or choosing the wrong bullet to begin with. I shoot one bullet type only out of my 7WSM. With my Tikka T3 in 260 Remington it’s still a work in progress and I’ve basically stopped due to the availability of necessary supplies. It has a slower barrel and I haven’t found it’s pressure limits nor it’s velocity node but I’m trying Hornady’s 140/143 grain ELD-X/M and H4350.
 

Kev1Doggy

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I had a good consistent load for my 6.5 CM with H4350 and 140 Berger, but have had no luck procuring either powder and bullets. I was on Powder Valley a while back and picked up 1k 139 Scenar L and bought 8lbs of RL16 so I am going to start working up a load and shooting that. I have heard good things on RL16 and 6.5 CM combination.
 
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