Help to Tighten Up My SD/ES on 6.5CM Gasser

[MNtadpole]

All,

So the last two trips to the range of resulted in me having unsatisfactory SD/ES values for my reloads. I have been most recently zeroing in on some velocity nodes using 140gr Barnes Match Burners, 41-ish gr H4350, Hornady brass, and WLR primers. Velocity node is appearing in the 2625-2630 fps.

When my SDs are single digit my shots are always tight, and as soon as my SDs break that, I get fliers. I understand that I'm using a gasser and my expectations for accuracy shouldn't be too high, but I think I can do better. I'm not a reloading genius, but I'm really thinking that my inconsistencies are coming from neck tension issues. Please feel free to point out any changes that you think I should make.

I have traditionally used a crimp after seating the bullet, which is where I think my inconsistencies are coming from. I originally decided that I should crimp due to only .002 approx. of neck interference being measured. I have been told that gasser should have between .003-.004 of measure interference at the neck.

Here are my reloading steps taken everytime:

1. Dirty brass goes into the wet tumbler with stainless media, dawn soap, and hot water for 45 mins
2. Tumbled brass gets drained, washed, and placed in a dehydrator for 2 hours or until dry.
3. Dry brass gets annealed via propane annealing machine. I used the red color change method to time the annealing process. I have verified this process is reaching ideal temperatures with tempilaq.
4. Brass is lubed and FL resized using a Redding National Match (this is non-bushing type) die set.

5. Resized lubed cases are wet tumbled again using hot water, dawn soap, and lemmi-shine for 15min.

6. Tumbled cases are put in a dehydrator for 2 hours or until dry.

7. Dry cases are trimmed using World Finest Trimer, then chamfered and deburred using a drill.

8. All finished cases are primed on Dillion 550C.

9. Primed cases are manually charged from a Charge Master using a funnel.

10. Charged cases receive a bullet using Redding National Match seating die w/ micrometer. Seems very accurate…

11. Cases with a seated bullet receive a light taper crimp from the Redding Taper Crimp die.

Ammo Box/ Range/ Shoot!

 

[TxWelder35]

Squeaky clean necks from SS pin cleaning can lead to issues. I would also skip the crimp. How far are you shooting?

put a 50-75ES in your ballistic calculator and see how big of a difference it makes.

I wouldn’t be unsatisfied with 10-15 SD out of a gasser.

 

[rustyinbend]

I think I'm missing something. If you don't use a bushing die, and you don't mandrel your necks after sizing, how are you assuring a consistent neck diameter and tension?

 

[MNtadpole]

Squeaky clean necks from SS pin cleaning can lead to issues. I would also skip the crimp. How far are you shooting?

put a 50-75ES in your ballistic calculator and see how big of a difference it makes.

I wouldn’t be unsatisfied with 10-15 SD out of a gasser.

So during load dev. I'm only shooting out to 100 yards. I plan on shooting between 300-700 300 yards with a developed load.

 

[whatsupdoc]

Dont Crimp the cases.

 

[MNtadpole]

I think I'm missing something. If you don't use a bushing die, and you don't mandrel your necks after sizing, how are you assuring a consistent neck diameter and tension?

Ha ha ha, almost sounds like a rhetorical question. I have less than a 1 year of reloading experience under my belt, so I have a lot to learn. I try to do as much research as I can, when I can.

With that being said, I guess I was assuming that a Redding National Match die set was going to get me the performance I needed. I've heard that an expander ball isn't the best option to go with...

Sounds like I need to invest in a mandrel set and bushing die. I was looking at the 21 Century Shooter mandrel https://21stcenturyinnovation.com/buy-online/ols/products/caliber-specific-expander-mandrel set. I was also looking at the Redding bushing die for 6.5CM https://www.midwayusa.com/product/1018049293 . Any thoughts on those products? How would you recommend me determine the ideal bushings to purchase?

 

[MNtadpole]

Dont Crimp the cases.

Rodger, so crimping will be no more.

 

[KnowNothing256]

Ha ha ha, almost sounds like a rhetorical question. I have less than a 1 year of reloading experience under my belt, so I have a lot to learn. I try to do as much research as I can, when I can.

With that being said, I guess I was assuming that a Redding National Match die set was going to get me the performance I needed. I've heard that an expander ball isn't the best option to go with...

Sounds like I need to invest in a mandrel set and bushing die. I was looking at the 21 Century Shooter mandrel https://21stcenturyinnovation.com/buy-online/ols/products/caliber-specific-expander-mandrel set. I was also looking at the Redding bushing die for 6.5CM https://www.midwayusa.com/product/1018049293 . Any thoughts on those products? How would you recommend me determine the ideal bushings to purchase?

I’ve got the 21st Century with black nitride turning arbor. Quite happy with it, and others have reported induced runout with the Redding bushing die. As in, runout increased after sizing in the die.

 

[MNtadpole]

I’ve got the 21st Century with black nitride turning arbor. Quite happy with it, and others have reported induced runout with the Redding bushing die. As in, runout increased after sizing in the die.

So is there a widely known manufacturer of go-to bushing dies? What do you recommend instead?

 

[KnowNothing256]

So is there a widely known manufacturer of go-to bushing dies? What do you recommend instead?

Redding is a widely known mfg of bushing dies, and there are plenty others that do similar work. Short Action Customs is putting out some very high-end bushing dies, AFAIK those are the current answer if you wanna go the bushing route. Others can vouch for their performance, I haven't used them, but everything I've read has been great.

I use the Forster FL sizing die, and am probably gonna have them do their custom neck honing option to give my Lapua brass 3 thou neck tension, then open it up one thou with my mandrel. It'd save time to just target 2 thou tension with the honing and skip the mandrel (this is essentially the same function as a bushing die), but that would make the neck ID susceptible to any irregularities on the OD that theoretically would get pushed into the bullet bearing surface since an outside-to-inside step would be the last brass movement before seating. The other downside to this is that if you change brass you could theoretically end up with too little neck tension.

For instance, if you honed for Lapua brass (neck brass wall thickness 0.014") and wanted 0.002" neck tension, you'd hone for 0.264 + 2 x (0.014) - 0.002 = 0.290". Then let's say you switched to Hornady for whatever reason (couldn't find Lapua, got a great deal, who knows), which runs about 0.0135" thickness. Well now your Hornady brass is only gonna get 0.001" of neck tension, which may not be enough for your needs.

Hope that provides more answers than questions, haha, but keep asking stuff if not.

 

[1moaoff]

All same lot of brass with same number of firings?
Annealing?
How are you measuring powder?

 

[whatsupdoc]

Dont go crazy changing everything up, keep your current setup just stop crimping the case.
Test the results and if satisfactory you can use the money for components to improve your shooting skills.

I have had excellent results with standard dies using the expander ball.

 

[Dthomas3523]

I think we already found the issue.

He’s using a non bushing die without the expander ball or a mandrel. His neck ID is going to be pretty tight.

 

[KnowNothing256]

Just reread his first post more closely, he said he's only getting 0.002" tension ("neck interference"), and that's why he crimped. Seems to me just skip the crimp, like others have said, and agreed with @whatsupdoc that he doesn't need to go fully retool or anything crazy.

OP, if you're already getting 0.002" neck tension, a mandrel will either do nothing (turning arbor) or reduce your neck tension (expander mandrel).

 

[whatsupdoc]

I think we already found the issue.

He’s using a non bushing die without the expander ball or a mandrel. His neck ID is going to be pretty tight.

He is using the expander ball, how is he getting .002 neck tension?

 

[Dthomas3523]

He is using the expander ball, how is he getting .002 neck tension?

I think I was wrong. I believe I was reading another poster’s assumption that was incorrect.

 

[vh20]

No real numbers to work with here. What kind of SDs and what size groups are you seeing at 100? How much are they opening up with the higher SDs vs the tighter ones? You can often shoot really small groups at 100 with an SD that sucks (but you’ll pay the piper at distance), so are you certain the SD is the cause and not something else? Recoil management is a different animal with a gasser, and takes some practice to learn if you’re only used to a bolt gun.

 

[MNtadpole]

All,

Thank you for taking the time to address my post. I'm going to be replying to all the questions you have asked. You all rock!

 

[MNtadpole]

Redding is a widely known mfg of bushing dies, and there are plenty others that do similar work. Short Action Customs is putting out some very high-end bushing dies, AFAIK those are the current answer if you wanna go the bushing route. Others can vouch for their performance, I haven't used them, but everything I've read has been great.

I use the Forster FL sizing die, and am probably gonna have them do their custom neck honing option to give my Lapua brass 3 thou neck tension, then open it up one thou with my mandrel. It'd save time to just target 2 thou tension with the honing and skip the mandrel (this is essentially the same function as a bushing die), but that would make the neck ID susceptible to any irregularities on the OD that theoretically would get pushed into the bullet bearing surface since an outside-to-inside step would be the last brass movement before seating. The other downside to this is that if you change brass you could theoretically end up with too little neck tension.

For instance, if you honed for Lapua brass (neck brass wall thickness 0.014") and wanted 0.002" neck tension, you'd hone for 0.264 + 2 x (0.014) - 0.002 = 0.290". Then let's say you switched to Hornady for whatever reason (couldn't find Lapua, got a great deal, who knows), which runs about 0.0135" thickness. Well now your Hornady brass is only gonna get 0.001" of neck tension, which may not be enough for your needs.

Hope that provides more answers than questions, haha, but keep asking stuff if not.

I think I'm grasping what you're saying here and the calculations you're showing. The only concept that I'm missing is with the term "honing" and when you use that measurement in the sizing process. Is the "honing" size the size you chose the neck to be upon initial resizing, based off of the bushing you've selected?

Here are my current case / bullet measurements as taken best with a digital calibers:
Barnes Match Burner 140gr bearing surface diameter: .263"
Hornady 6.5CM average case thickness: .013"
Hornady case outside diameter after resized in Redding die: .289"
Dummy cartridge (same components) neck diameter: .290"

I think I need to read some more publications on these calculations. I guess I'm just needing some guidance on where I'm at currently. I feel like I'm over thinking the process.

 

[MNtadpole]

All same lot of brass with same number of firings?
Annealing?
How are you measuring powder

My brass is segregated to keep track of the lot's firing number. So yes, all the same number of firings.

I anneal every time before FL resizing. Yes.

I'm throwing powder with a RCBS Charge Master. I drop the programmed charge and wait until the final reading after the beep from the machine. If it over/under throws, I adjust accordingly.

 

[MNtadpole]

Dont go crazy changing everything up, keep your current setup just stop crimping the case.
Test the results and if satisfactory you can use the money for components to improve your shooting skills.

I have had excellent results with standard dies using the expander ball.

Seems like easy enough advice. I'd really like to have a solid calculation on what my current neck tension is. I feel like I might have miss calculated it originally, when I decided to process my reloads with a crimp.

 

[KnowNothing256]

I think I'm grasping what you're saying here and the calculations you're showing. The only concept that I'm missing is with the term "honing" and when you use that measurement in the sizing process. Is the "honing" size the size you chose the neck to be upon initial resizing, based off of the bushing you've selected?

Here are my current case / bullet measurements as taken best with a digital calibers:
Barnes Match Burner 140gr bearing surface diameter: .263"
Hornady 6.5CM average case thickness: .013"
Hornady case outside diameter after resized in Redding die: .289"
Dummy cartridge (same components) neck diameter: .290"

I think I need to read some more publications on these calculations. I guess I'm just needing some guidance on where I'm at currently. I feel like I'm over thinking the process.

Honing is a service that Forster offers where they will open up the neck portion of the sizing die, which results in it not squeezing the neck down as far. You can either order the die with it honed (not recommended for you, better to get it, take measurements, then make a decision), or send it in anytime after you've bought it and have them open it up. You do this to minimize working the brass excessively during sizing operations; there's no need to squeeze the neck waaaay down, then open it back up most of the way, when you could just squeeze it exactly the right amount. That's the objective of having one of your FL sizing dies honed. My specific die, with Lapua brass, takes the neck OD down to 0.283", then the mandrel opens it up to 0.2875"; this means that technically my FL die is over-working the neck by 0.0045", and I could have it honed to reduce or eliminate that excessive OD reduction.

Clear as mud?

 

[MNtadpole]

No real numbers to work with here. What kind of SDs and what size groups are you seeing at 100? How much are they opening up with the higher SDs vs the tighter ones? You can often shoot really small groups at 100 with an SD that sucks (but you’ll pay the piper at distance), so are you certain the SD is the cause and not something else? Recoil management is a different animal with a gasser, and takes some practice to learn if you’re only used to a bolt gun.

Here are my current case / bullet measurements as taken best with a digital calibers:
Barnes Match Burner 140gr bearing surface diameter: .263"
Hornady 6.5CM average case thickness: .013"
Hornady case outside diameter after resized in Redding die: .289"
Dummy cartridge (same components) neck diameter: .290"

MagnetoSpeed Data:

To give context to this load, I believe I identified a velocity node at approx. 2620-2640fps. My goal was verify that my suggested charges from Gordon Reloading Tool were giving me near accurate real-world velocities. It was pretty close.

To answer your question on whether the SDs are causing the fliers or something else, IDK anything for sure. I was doing my best to watch the Chrono data as I shot. I witnessed a theme of fliers followed by velocity deviations being recorded, so I naturally associated them as cause and effect. A decent grouping for me was approx. 1moa at 100 yards. The fliers seen would break the 1moa cluster an be like 3-4inches out.

My goal is to obtain the most repeatable results at 100yards, so I can get to the 700 yard range without it being a complete disaster lol.

 

[MNtadpole]

Honing is a service that Forster offers where they will open up the neck portion of the sizing die, which results in it not squeezing the neck down as far. You can either order the die with it honed (not recommended for you, better to get it, take measurements, then make a decision), or send it in anytime after you've bought it and have them open it up. You do this to minimize working the brass excessively during sizing operations; there's no need to squeeze the neck waaaay down, then open it back up most of the way, when you could just squeeze it exactly the right amount. That's the objective of having one of your FL sizing dies honed. My specific die, with Lapua brass, takes the neck OD down to 0.283", then the mandrel opens it up to 0.2875"; this means that technically my FL die is over-working the neck by 0.0045", and I could have it honed to reduce or eliminate that excessive OD reduction.

Clear as mud?

Understood actually. Yea, I can see the benefit of not over working the brass if you don't need to.

 

[KnowNothing256]

Here are my current case / bullet measurements as taken best with a digital calibers:
Barnes Match Burner 140gr bearing surface diameter: .263"
Hornady 6.5CM average case thickness: .013"
Hornady case outside diameter after resized in Redding die: .289"
Dummy cartridge (same components) neck diameter: .290"

MagnetoSpeed Data:
View attachment 7582655
To give context to this load, I believe I identified a velocity node at approx. 2620-2640fps. My goal was verify that my suggested charges from Gordon Reloading Tool were giving me near accurate real-world velocities. It was pretty close.

To answer your question on whether the SDs are causing the fliers or something else, IDK anything for sure. I was doing my best to watch the Chrono data as I shot. I witnessed a theme of fliers followed by velocity deviations being recorded, so I naturally associated them as cause and effect. A decent grouping for me was approx. 1moa at 100 yards. The fliers seen would break the 1moa cluster an be like 3-4inches out.

My goal is to obtain the most repeatable results at 100yards, so I can get to the 700 yard range without it being a complete disaster lol.

You’re probably gonna need to take the chrono off to see on-paper performance, just FYI, although 3 MOA fliers probably aren’t the Magnetospeed unless you’re getting bullet strikes on it.

 

[MNtadpole]

Redding is a widely known mfg of bushing dies, and there are plenty others that do similar work. Short Action Customs is putting out some very high-end bushing dies, AFAIK those are the current answer if you wanna go the bushing route. Others can vouch for their performance, I haven't used them, but everything I've read has been great.

It looks like Short Action Customs only makes a neck sizing bushing die. Are all bushing dies only neck sizers? If I was going the bushing route, I was kind of hoping to do FL size.

 

[MNtadpole]

You’re probably gonna need to take the chrono off to see on-paper performance, just FYI, although 3 MOA fliers probably aren’t the Magnetospeed unless you’re getting bullet strikes on it.

LOL if the bullet struck the Magneto sensor, there probably would have been a plastic explosion. I'd be pissed the day that happens. In all seriousness, the sensor hasn't been struck. I can say that for a fact. I get what you're saying about removing the magneto speed, due to the device affecting barrel harmonics and blah blah. Good point.

 

[KnowNothing256]

It looks like Short Action Customs only makes a neck sizing bushing die. Are all bushing dies only neck sizers? If I was going the bushing route, I was kind of hoping to do FL size.

Nah, their “Precision Resizing Die” is a FL size that‘s designed to bump the shoulder, give special attention to the base of the case (which can swell after numerous firings and I guess other FL dies don’t hit that spot as well?), and resize the neck using a bushing. I think it also leaves the very base of the neck unsized to try to avoid donut issues.

Give ‘em a ring tomorrow, I’m sure they can explain better than me. I’m kinda curious myself how they decided where to set the shoulder bump, since that’s usually an intermediate reloading technique that is classically considered chamber-dependent.

 

[vh20]

Here are my current case / bullet measurements as taken best with a digital calibers:
Barnes Match Burner 140gr bearing surface diameter: .263"
Hornady 6.5CM average case thickness: .013"
Hornady case outside diameter after resized in Redding die: .289"
Dummy cartridge (same components) neck diameter: .290"

MagnetoSpeed Data:
View attachment 7582655
To give context to this load, I believe I identified a velocity node at approx. 2620-2640fps. My goal was verify that my suggested charges from Gordon Reloading Tool were giving me near accurate real-world velocities. It was pretty close.

To answer your question on whether the SDs are causing the fliers or something else, IDK anything for sure. I was doing my best to watch the Chrono data as I shot. I witnessed a theme of fliers followed by velocity deviations being recorded, so I naturally associated them as cause and effect. A decent grouping for me was approx. 1moa at 100 yards. The fliers seen would break the 1moa cluster an be like 3-4inches out.

My goal is to obtain the most repeatable results at 100yards, so I can get to the 700 yard range without it being a complete disaster lol.

As I suspected, the magnitude of the SDs you're getting are in no way large enough to cause the performance issues you describe. Look for another cause.

I found some old Hornady 147 ELD Match ammo that got left in the back of the barn for a couple of years (no climate control, exposed to temps well over 100 inside in the summer). The cases were tarnished and the bullets looked nearly brown. I tried them out and shot a 10-shot string, including a 3-shot group at 100 to establish zero before going to distance. The 3-shot group was just under 1/2 MOA. At the end of the 10 shot string (the remaining 7 fired at 1070 yds), the vertical stringing was horrendous, and the ES was 123 (don't recall the SD, but ridiculous, like mid-40s). But even at that, it still shot well at 100.

 

[whatsupdoc]

Your measurements may not be correct.

"Barnes Match Burner 140gr bearing surface diameter: .263"

No way are they .263 they are .264 maybe your caliper is bad.

 

[MNtadpole]

Your measurements may not be correct.

"Barnes Match Burner 140gr bearing surface diameter: .263"

No way are they .263 they are .264 maybe your caliper is bad.

I would never rule out that as a possibility, since I've never measured it against a calibrated surface. Any idea on how to verify this? It's a Hornady branded calipers. I understand that its not a fancy Mitutoyo. Maybe the battery needs replacement.

Heres a picture of the Barnes Match Burners:

 

[KnowNothing256]

I would never rule out that as a possibility, since I've never measured it against a calibrated surface. Any idea on how to verify this? It's a Hornady branded calipers. I understand that its not a fancy Mitutoyo. Maybe the battery needs replacement.

Heres a picture of the Barnes Match Burners:
View attachment 7582930

I wouldn't worry too much about it, since most of your measurements using calipers are gonna be comparing things. I also suspect my calipers of underreporting sizes (they mic'd my turning arbor one thousandth smaller than it's supposed to be), worried about it for a while, then realized it didn't matter.

The vast majority of your caliper measurements are gonna be for things like headspace when bumping shoulders (comparing fired vs bumped shoulders) and bullet seating depth (comparing seated bullet vs target, which you'd have determined using these same calipers), and as long as you don't change calipers all the time, your tool's error will be irrelevant. You'll very occasionally check neck OD when sizing cases, and other stuff you might end up curious about, but one thousandth off at 0.264" (less than 0.4% error) in absolute numbers isn't gonna hurt you (or me lol) anywhere I could think of.

 

[Bullspotter]

Here are my current case / bullet measurements as taken best with a digital calibers:
Barnes Match Burner 140gr bearing surface diameter: .263"
Hornady 6.5CM average case thickness: .013"
Hornady case outside diameter after resized in Redding die: .289"
Dummy cartridge (same components) neck diameter: .290"

So outside of a sized case is .289, minus the case thickness of .013 X 2 would make the inside Dia .263 the same DIA of the bullet. Looks like not enough neck tension to me.

I had a lot of the same issues with my 260 Gasser, Found the bullet was sliding out of the case into the lands when it was chambering a round. I made adjustments to tighten the neck tension, Ended up with a .290 bushing with lapua brass, gave me a inside DIA of .258, Out side DIA of .290. Wall thickness of .016. Loaded round outside DIA is .2935. No more bullet movement, My ES/SD went way down, and flyers went away.

I would go to the range, load a round in chamber by hand, close bolt, put 2 rounds in a magazine, fire it, then pull the round out of the chamber and measure COAL.

Also get a set of spark plug gap gauges and test your calipers for accuracy maybe.