Reloading 6.5 Creedmoor

[Fuj']

Fuj', can you explain what 1.3 as calculated is referring to?

The Miller stability calculators used by JBM and others list the stability numbers as 1.3 as the
minimum and 2.0 as maximum. Simply put, under 1.3, you run the risk of key holing and over
2.0, would mean over spinning and possibly blowing bullets up. JBM is a free online calculator.
Very simple to use. I have several I use, but JBM is quick when checking stabilities.

And Mr. Hoback.....Why would I recommend a twist without knowing the bullet and speed you'll
be dealing with. If your ordering up a 1:7.5 twist, that's fine if you did the math.

[charlie b]

For the most part I rely on the bullet mfg to determine twist for stable bullets....BUT....it is not written in stone. The muzzle velocity is a large factor in this. Drive a bullet 100fps faster and the spin rate is that much higher with a higher stability factor.

Keep in mind the Miller stability equation is a simplification of the basic stability equations. The main points are they assume a bullet profile that looks like a football and the velocity range is intended to be near Mach 2.5. The fine points of bullet design can make the calculated number off a bit. It is a good guide, but, again, not definitive.

Working with Sierra 77SMK's in 1:9 twist barrels. Sierra recommends 1:8 or faster but the 1:9 works in many rifles, at least when the velocity is closer to max. Maybe if you use a 16" barrel and subsequent slower velocity then a 1:8 will be necessary, or maybe Sierra is just being conservative and want the bullets to be stable at minimum book loads.

Last, when working 'near the edge' atmospheric conditions can change enough to upset the stability. Much colder or warmer, higher or lower elevation, humidity can all change the stability of the bullet. Some variations of the Miller equation (like JBM) allow input of temp and pressure due to this.

[Ernest T]

The Miller stability calculators used by JBM and others list the stability numbers as 1.3 as the
minimum and 2.0 as maximum. Simply put, under 1.3, you run the risk of key holing and over
2.0, would mean over spinning and possibly blowing bullets up. JBM is a free online calculator.
Very simple to use. I have several I use, but JBM is quick when checking stabilities.

And Mr. Hoback.....Why would I recommend a twist without knowing the bullet and speed you'll
be dealing with. If your ordering up a 1:7.5 twist, that's fine if you did the math.

Thanks, I'll play around with that calculator to see what I can learn.

[Ernest T]

I loaded a few different powders and bullets this week.

This was 42 grains of RL-16 with 140 grain Barnes Match Burner bullets, loaded at seating depths of 2.260, 2.220 and 2.180 in two three shot groups. I was following the advice in the Berger manual for loading VLD bullets. The top left and middle right were loaded to 2.260. The top right and bottom left were loaded at 2.220. Finally, the middle left and bottom right were loaded to 2.180. The first group at 2.180 averaged 2658 FPS with an ES of 17 and SD of 7. The second group averaged 2659 with an ES of 29 and SD of 12. I don't think I've shot a bad group with this powder and bullet. I think I'm going with 2.180 since it will load in a magazine, but the others weren't that bad either.

9315

I used this target for varying loads of H4350 with 140 grain Nosler RDF bullets with a seating depth of 2.298 which is at the lands. I really like that 41.4 grain group. That group averaged 2642 with an ES of 10 and SD of 4. The ES and SD numbers were much smaller with Hogdon 4350 than RL-16 or Winchester 760. Notice I don't have any measurement on the middle right target? I don't know where the third bullet went. I don't think its likely I missed the target entirely, but I can't say it went in one of the other holes either. I only shot two rounds at the bottom left target as I had a misfire with one.

9316


This was Winchester 760 loaded with 140 grain Berger Target VLDs. I extrapolated data from the Hornady manual and Barnes website to come up with the min and max loads for this combo as the Berger data seemed to call for very low loads. The brass didn't show pressure signs at any of these loads. It's an interesting target as the initial impacts were much lower than those with RL-16 or H4350. I adjusted the scope up after the first three groups. I don't have good data for ES and SD because about every other shot failed to record on the chronograph. Velocity varied from just below 2600 to 2665 at the max load today.

9317
9318

[charlie b]

So the top target were all the same except seating depth? And no scope change? So you should overlay each pair of groups to give you 6 round groups. Will give you a better idea of which seat depth is better.

When it boils down to the final 'settings' I shoot a minimum of a 5 round group. The only time I shoot less than 5 rounds is the initial velocity ladder (which is 3rnd each). There are enough data points that I can identify a trend (most of the time).

I only mention because I have had to redo a series. The 3 round groups looked wonderful. But, a 5 round series showed a different preference.

[Ernest T]

So the top target were all the same except seating depth? And no scope change? So you should overlay each pair of groups to give you 6 round groups. Will give you a better idea of which seat depth is better.

When it boils down to the final 'settings' I shoot a minimum of a 5 round group. The only time I shoot less than 5 rounds is the initial velocity ladder (which is 3rnd each). There are enough data points that I can identify a trend (most of the time).

I only mention because I have had to redo a series. The 3 round groups looked wonderful. But, a 5 round series showed a different preference.

I'll start shooting five round groups now that I'm close. I just didn't want to waste the powder, primers and bullets on loads that weren't close.

[charlie b]

Understand. For me it's the kind of thing that a 3rnd bad group will show a bad load, but, a good group may not be a good load.

And then there is the 'me' factor. Sometimes a bad group is just me not shooting well. I tend to get that a lot more than I'd like :)

[Ernest T]

For anyone interested, Graf and Son's had H4350 in 8 lb jugs today.

[Robinhood]

I used this target for varying loads of H4350 with 140 grain Nosler RDF bullets with a seating depth of 2.298 which is at the lands. I really like that 41.4 grain group. That group averaged 2642 with an ES of 10 and SD of 4. The ES and SD numbers were much smaller with Hogdon 4350 than RL-16 or Winchester 760.

Very common consensus. Wait untill you take it out to 500 plus.

[South Prairie jim]

9327I like this one

[Ernest T]

9327I like this one

Me too!

[Ernest T]

I'm going try IMR 4350 with the 140 grain Berger VLD's this week to see how they do with that powder.

[Ernest T]

I've been so busy with other stuff I haven't made it to the range in awhile, this weekend I got some time to reload so I'm working on three different things at once.

I'm narrowing down a powder charge for H4350 and the Nosler 140 gr. RDF bullets. I loaded 5 each at 41.4, 41.6, 41.8 and 42 gr. at 2.298 CBTO which is at the lands. This is a follow-up to a load I was working on a few weeks ago using 3 shot groups. All these shot sub MOA and the 41.4 was sub 1/2 MOA. I was having problems with the chronograph at 41.8 and 42 so I am hoping to get the data I missed the other day.

I'm also working on RL-16 and 140 gr. Barnes Match Burner bullets. I have identified a good load, 42.0 gr. and had pretty good results at 2.180 CBTO -- that will fit in my magazine. I loaded 5 rounds each at 2.182, 2.180 and 2.178 to see what would happen.

Finally, I wasn't happy with the Win 760 and Berger VLD Target bullets so I'm trying IMR 4350. The Berger Manual doesn't have loads for this powder, but the Hornady book has loads for it using 140 Gr. ELD-M bullets so I'm using that data. I'm starting at mid-range and working my way up to max .002 gr. at a time.

[GrenGuy]

“.002 grains at a time” ? Whow! That’s about a tenth of a kernel of IMR 4350 ! :o

[Ernest T]

“.002 grains at a time” ? Whow! That’s about a tenth of a kernel of IMR 4350 ! :o yeah, that's a typo, I meant .2 grains!

[Ernest T]

It was supposed to drizzle and sprinkle today and the wind was blowing like crazy, but I went to the range anyway because the forecast isn't much better for tomorrow or Monday. I don't like to go on Saturday or Sunday because of the crowds.

9387

The first rounds I shot were with H4350 and 140 grain Nosler RDF. The Nosler data is pretty conservative with a max of 41 Gr of H4350 pushing the 140 grain bullet at 2694 FPS out of a 24" barrel. Hornady says the max load for H4350 for a 140 gr ELD-M is 42 gr so I felt pretty safe working up from 41 to 42 gr of H 4350 with the Nosler. This is what I got. I moved the scope up 1 MOA after the first group. None of the cases or primers showed signs of overpressure and the 42 gr. shot the best group although they all looked pretty good for me. The velocity at 42 gr. was 2727 FPS out of my 22" barrel.


9388


Then I moved on to RL-16 and 140 gr. Barnes Match Burners. I also shot this last time and liked 42 gr. of RL-16 with a length of 2.180 CBTO. I was looking to see if moving the CBTO up or down looked like it would make a difference and it didn't.



9390

9391

Then I shot 140 gr. Berger VLDs with IMR 4350. The Berger manual said they got the best accuracy with the VLDs with IMR 4350. I loaded all of them at the lands, 2.284 CBTO and they all shot about the same. I was going to shoot the fouler rounds into the bottom of the paper, but the scope was adjusted up an MOA, that's why they were so far apart.

9392

[Ernest T]

About three months ago I started using CCI 450 magnum SRPs and the ES and SDs of my rounds decreased sharply. I didn't see a corresponding increase in accuracy, at least I didn't think I did, but I did notice I started getting misfires. At first it was one every 100 rounds or so, but lately it has been increasing. This was a batch of 140 gr. ELD-M rounds I loaded just after Christmas. I finished them off today and 5 out of 38 failed to fire.

9399

The primers don't look any different than they did before.

9400

It got worse as I started shooting rounds I made in the last week, until I'd estimate 25% failed to fire. I came home and took the rounds apart and tried to figure out what was going on. I measured the primer pockets and 95% were within the .121-123 spec. A few were at .123.5 or .124 and one was .120. Nothing that should have caused an issue. I took the unfired primers and wacked them with a hammer and I had to flatten them to make them fire. If I didn't hit it with conviction, it wouldn't fire. Great I think I've found the problem. I reloaded the founds, half with SRPs and half with Magnum SRPs to see if there was a difference in performance between the two.

9401

9402

9403

One last thing I did, and the reason for this post, is I took the firing pin out of the bolt to see if it had gunk keeping it from striking the primer with enough authority to fire it. That's when I noticed this bolt that holds the handle on the rear of the bolt/firing pin was not tight. As in I took it of by hand. I'm thinking that is my real problem?

9404

I took the firing pin out and cleaned it, but it really wasn't that dirty. I put it back together without lube, but it seems like I should have at least oiled it? I question that because I have two Springfield Arms handguns that have a similar firing pin arrangement and lubing it will cause the gun to malfunction in short order. While I had the firing pin out of the bolt, I chucked it into my drill press and sanded that round point to be a little blunter with 2000 grit sand paper. I didn't take much off because I wanted to creep up on it and not mess it up by taking too much off.

9405

One last thing, Does the tail on that spring hold the round-head pin in the bolt? It came apart before I got a good look at it. I put it back that way because it seemed like the only way it'd work, but I want to confirm that.

9406

[charlie b]

I would assume it does. I wonder if clipping off that piece will allow the firing pin to fall with less resistance?

I do lube firing pins, but, only with dry graphite.

[vince_ross]

I would NOT clip anything from that spring that holds the cocking pin in place. If you're having a hard time pulling it or putting it back together, you can straighten it a little, but don't remove any material. I also see that you have a bolt lift kit installed, but I have a question....Where is your spacer for the BAS nut/bolt? I've had a few installed on my guns and they all had spacers that were needed.

9411

9412

Edit:

Sorry, the spacer I was asking about is shown in this video. Skip to just after the 2:00 mark to see your firing pin config.

https://www.youtube.com/watch?v=4o7MqSUW-5U

[Ernest T]

I would NOT clip anything from that spring that holds the cocking pin in place. If you're having a hard time pulling it or putting it back together, you can straighten it a little, but don't remove any material. I also see that you have a bolt lift kit installed, but I have a question....Where is your spacer for the BAS nut/bolt? I've had a few installed on my guns and they all had spacers that were needed.

9411

9412

Edit:

Sorry, the spacer I was asking about is shown in this video. Skip to just after the 2:00 mark to see your firing pin config.

https://www.youtube.com/watch?v=4o7MqSUW-5U

it went back together and seems to work fine. It didn’t have that big washer. I don’t think there’s enough room for one and the knob on my gun is different that that shown in the video.