I have an issue with 6.5 Creedmoor or maybe just reloading

[AntiPattern]

Here is a Quickload model of info you have provided, of coarse I don't have your actual case capacity, so I took case cap down to 52 gr. By this you are 5K under max pressure. RL 17 is an extremely high energy powder, I say more so than VV N 500 series, I would not let speed dictate anything in this equation.



View attachment 198832

This is what I've been playing with... I bumped my cave volume down to get the pressures closer to where I thought they would be.

 

[AntiPattern]

By the way, anyone who is interested, Gordons Reloading Tools is a free download... I really like it and as long as you put in the correct #'s, it is usually pretty good. It can also take what you want to do with a projectile and recomment powders that will get you closest. Pretty well thought out. https://grtools.de/. They shoot guns in Denmark, too.

 

[dok7mm]

I noticed you're using the seating depth number from an online reloading site.

May I suggest that may not be the way that works best in your rifle.

The Hornady tool and the split case neck have been used for years for some decent results, but when compared to the stripped bolt, the other methods will actually be in the lands to a degree depending on your expertise. This is a critical measurement and can make a big difference in pressure, especially when your bullets may have a lot of variance.

Step1- Find the "accurate" seating depth where your ogive is just free of touching the lands, preferred is the stripped bolt method.

Step 2- When you get that number, write it down. Also write down your COAL length. This is the basis that you will use to determine the true (best) seating depth for accuracy in YOUR barrel with that one bullet weight & model. You have to do step 1 with different bullets, if you change.

Step 3- To find your right seating depth, use a starting load, seat 3 rounds .010" deeper in case than your initial "touch". Next load 3 @ .015, @.020" @ .025" off lands, then @ .030" off and so on. You should find a tight 3 shot group somewhere between .010" jump and .045" jump. You will also find your pressure declines as you move off from being against lands. Once you find the seating depth that shows the tightest group @ 100 yards, use that seating depth to do your powder work-up.

As I stated in my earlier post, use your Hornady bullet comparator to measure the base of case to where your comparator hits the ogive, that's CBTO and is the measurement that counts. COAL means little, except to fit your magazine.

Keep good notes on everything you do. Spend some time measuring your results. If you have a chronograph, record velocity on every shot. Rely on the results you find in YOUR rifle, bullet & powder.

 

[oldpilot]

I reloaded some rounds that I wanted to test using 140 RDF and RL-17. I tried to be super careful and meticulous with these loads. I loaded up a group of 25. From 41.1 to 42.3 in .3 increments. I'm using Hornady brass and CCI #200 primers. The first group I shot I was hitting 2850fps. When I got the 41.4 group, I had 2 shots at 2900 fps and blew a primer. Stopped there. I should have been seeing around 2700 - 2725 with these 2 loads. I purchased a Lyman digital scale with trickler. I would assume this would be a decent unit. I have re-calibrated, zeroed, etc. This is the second time I've loaded a group only to have them way hotter than expected. I set the oal at 2.87 because I measured my rifling at 2.9 and these still fit in my AI mags. I'm shooting a Thompson Performance Center LRR in 6.5 with a 24" barrel.

Where do I start figuring this stuff out? My only guess is that my powder grains reading is off and the scale is reading lighter than it should.

First, my moth

I reloaded some rounds that I wanted to test using 140 RDF and RL-17. I tried to be super careful and meticulous with these loads. I loaded up a group of 25. From 41.1 to 42.3 in .3 increments. I'm using Hornady brass and CCI #200 primers. The first group I shot I was hitting 2850fps. When I got the 41.4 group, I had 2 shots at 2900 fps and blew a primer. Stopped there. I should have been seeing around 2700 - 2725 with these 2 loads. I purchased a Lyman digital scale with trickler. I would assume this would be a decent unit. I have re-calibrated, zeroed, etc. This is the second time I've loaded a group only to have them way hotter than expected. I set the oal at 2.87 because I measured my rifling at 2.9 and these still fit in my AI mags. I'm shooting a Thompson Performance Center LRR in 6.5 with a 24" barrel.

Where do I start figuring this stuff out? My only guess is that my powder grains reading is off and the scale is reading lighter than it should.

My mother went to grade school with Jack Elam so if you're anything like your avatar you are a nice guy! I have purchased 4 digital scales, the last a jeweler's digital. It about $30 more than the others, but is so much more accurate and versatile. I gave away the R and L scales and kept the Dillon and the jeweler's. I was surprised how inaccurate and unstable the calibration was on the R and the L.

 

[ntsqd]

I'm no help with the topic, I just wanted to give a thumb's up for using Jack's pic as an avatar!
Oldpilot, your mother likely knows the story of the screwy eye since it was grade school. Growing up he was my neighbor's poker playing buddy when they weren't on set together. And maybe then too!

 

[AntiPattern]

I noticed you're using the seating depth number from an online reloading site.

May I suggest that may not be the way that works best in your rifle.

The Hornady tool and the split case neck have been used for years for some decent results, but when compared to the stripped bolt, the other methods will actually be in the lands to a degree depending on your expertise. This is a critical measurement and can make a big difference in pressure, especially when your bullets may have a lot of variance.

Step1- Find the "accurate" seating depth where your ogive is just free of touching the lands, preferred is the stripped bolt method.

Step 2- When you get that number, write it down. Also write down your COAL length. This is the basis that you will use to determine the true (best) seating depth for accuracy in YOUR barrel with that one bullet weight & model. You have to do step 1 with different bullets, if you change.

Step 3- To find your right seating depth, use a starting load, seat 3 rounds .010" deeper in case than your initial "touch". Next load 3 @ .015, @.020" @ .025" off lands, then @ .030" off and so on. You should find a tight 3 shot group somewhere between .010" jump and .045" jump. You will also find your pressure declines as you move off from being against lands. Once you find the seating depth that shows the tightest group @ 100 yards, use that seating depth to do your powder work-up.

As I stated in my earlier post, use your Hornady bullet comparator to measure the base of case to where your comparator hits the ogive, that's CBTO and is the measurement that counts. COAL means little, except to fit your magazine.

Keep good notes on everything you do. Spend some time measuring your results. If you have a chronograph, record velocity on every shot. Rely on the results you find in YOUR rifle, bullet & powder.

Actually, all the numbers are configurable. I think it bases the seating depth on what you select as your oal, projectile length and case length most likely. Those are just what I had put in.

I really appreciate all the information you guys are sharing. I'll add your steps to my reloading bible. Lol. Anyone who thinks this is easy is a fool. Maybe that was my problem when I started. I thought it might be easier than it actually is and rushed through. I'll make sure to take my time from now on.

 

[AntiPattern]

Wow! My check weights came today. That was way faster than expected. I'll try to get the scale verified and pull apart some of my rounds to see if I over charged or what.

 

[NATE40]

If you can extend your seating depth a little. That would have a significant reduction in pressure without reducing velocity. Also weighing brass and sort by weight and use the lightest set. And keeping loaded shells cool.
If you can increase case capacity without reduction in load it will reduce pressure. I feel the first 2 rounds fired were lighter brass,seated a little deeper or the one round was warmer. Temperature is also a factor. Winter loads can cause problems in summer. reducing your load for summer vs winter may help. A program called quick load may help you obtain the perfect load for your area.

 

[AntiPattern]

Well, I pulled a couple apart and the powder weights are with .1 grain. All I can think is that I'm jamming the lands. I'm going to push back .050 to 2.085 COAL and try it again.

 

[AntiPattern]

This information and lengths I ams spouting off are for my 6.5 Creedmoor.

Ok. What I figured out is that some of the bullets I was using to reload would measure 2.805 but the CBTO (Base To Ogive) measurement was at 2.30 which is the jam point on my gun. I actually had to shorten some to get the pressures to go down to normal.

So, I have learned to measure both COAL and CBTO when I start using a new bullet. When I loaded up some 156gr Berger Elite hunters at 2.805, the CBTO is way back at 2.10 and if I push them to my sweet spot of 2.20 which is where I want my CBTO, they are too long to fit in the mag and the COAL is around 2.90 so I would probably end up loading one at a time if I wanted these or push them back from my current sweet spot of 2.20. 140 gr SPEER, I have to load to around 2.72 COAL to get a 2.20 CBTO. There are HUGE differences between bullets which is something I wasn't aware of as a newby. Be sure you aren't jamming the barrel if you are measuring COAL. Depending on which bullet you use, one could be jamming and one could be too far back on CBTO while the COAL is the same length.

I really scratched my head on this one for a while folks.

Thanks for all the info along the way!

 

[ShtrRdy]

Step 3- To find your right seating depth, use a starting load, seat 3 rounds .010" deeper in case than your initial "touch". Next load 3 @ .015, @.020" @ .025" off lands, then @ .030" off and so on. You should find a tight 3 shot group somewhere between .010" jump and .045" jump. You will also find your pressure declines as you move off from being against lands. Once you find the seating depth that shows the tightest group @ 100 yards, use that seating depth to do your powder work-up.

Is it absolutely necessary to step the seating depth in 5 thou increments? Are 10 thou steps too big?

 

[338 dude]

Dok 7MM method sounds good to me .010 adjustments would be a rough seating depth test to me

 

[QuietTexan]

There are HUGE differences between bullets which is something I wasn't aware of as a newby.

Yes, you have to set seating depth on each bullet, not just one depth for the rifle. I load Nosler 140 Partions and Hornady 143 ELD-X into my 6.5 Creedmoor, and the two bullets have different COL/BTO measurements. Interesting that different bullets never seemed to come up in this thread.

I bought a pack of 20mL screw top bottles, and keep every one of my "measuring" bullets. One bullet of each and every bullet brand/style/weight I've ever loaded gets saved in a bottle (6mm I can put 4-5 in a bottle, .338 maybe two), with the specs on that bullet written down in my loading log. Bullet length and base to ogive and measured on each. That way I have a baseline to compare to, be it a new batch of the same type of bullets or for measuring throat erosion, and I always have one around if I shoot off the rest of the ones I bought.

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Is it absolutely necessary to step the seating depth in 5 thou increments? Are 10 thou steps too big?

Depends on the cartridge and bullet, and if you want to load that tight to the lands. Some people swear you have to be close, but other people seem to be fine with longer jumps. I initially move in 0.040" increments per the Berger guidelines. Then I'll straddle the best grouping at +/- 0.010". If I moved in 0.005-0.010" increments I'd shoot 100 rounds just doing seating depth testing. I find many hunting bullets work perfectly fine around book COL, which tends to be a long jump.

I just checked some notes, book COL for my 243 Win is 0.180" off the lands with Sierra 95 HPBTs, and my 300 RUM is at 0.229" off with Berger 210s. I'm not sure the neck is long enough on a 243 case to load that bullet into the lands on my rifle, to get it to touch I think I'd be less than half a caliber in the neck. Defiantly less than the 80% that I use as a guide on hunting rounds. The 300 RUM on the other hand has the 210s loaded out to the point I'm debating between two Wyatt's mag boxes because I'm getting close to 3.900" COL with those.

This is why the hobby is entertaining, never anything set in stone.

 

[Deputy819]

Is it absolutely necessary to step the seating depth in 5 thou increments? Are 10 thou steps too big?

Tagging in....