Node help

021411

021411

hot loads B==D - - -
Full Member
Minuteman
Dec 14, 2011
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Houston, TX
#1
Despite the crappy weather today in my neck of the woods I went to the range to fire off 11 rounds loaded up in 0.2 gn increments.

6.5 CM 140 ELD-M loaded at 2.1130" CBTO. H4350 charges were thrown with a Chargemaster Lite. The powder I have is a few years old and it was about 55 degF out.

41.0 2644
41.2 2655
41.4 2680
41.6 2684
41.8 2714
42.0 2722
42.2 2741
42.4 2778
42.6 2761
42.8 2784
43.0 2781

I kept an eye on pressure signs. Everything looked good. Based on my data, should I be looking at 42.4-42.8? If so, where should start the next load at?
 
Last edited:
#2
Your CBTO seems short. What did factory ammo measure at?

I load to 2.200 even CBTO.

Here is my load 10 round test for example out of a 26" barrel.
41.8 -2742
42.0 -2745
42.2 -2754
42.4 -2767
42.6 -2770
42.8 -2791
43.0 -2797 (Slight extractor mark)
43.2 -2823 (Little more extractor mark)
43.4 -2829 (Ejector mark)
43.6 - Did not fire

As you can see that my numbers are a slight increase in velocity with two flat spots pretty close together. I have no idea which one will be better but I am going to run 10 rounds of 41.9 and 10 round of 42.5 in the morning to see what they do.

I loaded them on a Chargemaster but double checked them on a Gempro 250 (which is very accurate. I suggest that you recalibrate your chargemaster every 5 rounds to get the most accurate powder drops. I find that if I calibrate every 5 rounds it is very close to the Gempro.
 
#7
I only had access to a small area about 40-50 yards due to the property I was at being SUPER muddy. The only thing I did yesterday was just chronograph. I did not shoot round robin.
 
#8
I like running every .1 grains when looking for a node because the more data I can get the better I can accurately choose a node to test for seating depths and it’s work good for me for the last two barrels I’ve shot. I also only have 200 yards at my place to do load development. Ideally I would like to have 600 yards so I could do a true ladder test and not relie on the magneto speed attached to the end of my barrel.
 
#9
100yd OCW is all you need. .1gr increments is completely unnecessary. I do .2gr increments within small, known windows at 100yds round Robin. Looks for those 2-4 charges that have similar POI then load in the center and do your seating depth test.

Yes I do load confirmation at 600yd but it's always dead on.
 
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#10
padom said:
100yd OCW is all you need. .1gr increments is completely unnecessary. I do .2gr increments within small, known windows at 100yds round Robin. Looks for those 2-4 charges that have similar POI then load in the center and do your seating depth test.

Yes I do load confirmation at 600yd but it's always dead on.
Click to expand...

Why is .1 completely unnecessary?

I like to collect as much data as I can so I know all the nodes. I do agree on shooting it round robin so that you can try and take the shooter error out of it.
 
#11
Colt1776 said:
Why is .1 completely unnecessary?

I like to collect as much data as I can so I know all the nodes. I do agree on shooting it round robin so that you can try and take the shooter error out of it.
Click to expand...

Because you dont need .1gr charges to find the center of a node. Your putting excess rounds down the barrel, for no gains. Read Dan Newberry OCW for exact info on OCW testing procedures
 
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#12
Hit my normal range this morning. It was chilly 49 degs and to be honest I could not feel my fingers at all and I pulled quite a few shots for sure.
All the rounds were loaded a smidge longer at 2.133" CBTO as a starting point this time.
My best group was with 42.2gn at 0.17" with a suppressor. I started to see ejector wipe starting at 42.3 all the way to 42.6.

Next round I'm going to try loading a little longer with 42.2gn.
 
#13
I think you may have the wrong impression of what a node is. If you haven’t read up on OWC I would recommend it, the whole goal is to have the same tight group that isn’t affected by slight variations in your loads, temp so on and so fourth.

And if you shot your best group .1 grain below pressure signs on a 49 degree day, you will be very sad on a 100 degree day trying to get your bolt open
 
#14
I'm all over the place right now with everything. Don't know where you are but here in SE Texas we have wild temp swings. Just a few days ago it was balmy and hot. The temp dropped two days ago and will gradually rise again later this week.
I was going for a 10 shot load development without getting into shooting a bunch of rounds. What is strange is that I didn't see any signs of pressure yesterday and I went up to 43gn.
 
#17
021411 said:
I'm all over the place right now with everything. Don't know where you are but here in SE Texas we have wild temp swings. Just a few days ago it was balmy and hot. The temp dropped two days ago and will gradually rise again later this week.
I was going for a 10 shot load development without getting into shooting a bunch of rounds. What is strange is that I didn't see any signs of pressure yesterday and I went up to 43gn.
Click to expand...
Where in South Texas are you?
 
#20
021411 said:
Despite the crappy weather today in my neck of the woods I went to the range to fire off 11 rounds loaded up in 0.2 gn increments.

6.5 CM 140 ELD-M loaded at 2.1130" CBTO. H4350 charges were thrown with a Chargemaster Lite. The powder I have is a few years old and it was about 55 degF out.

41.0 2644
41.2 2655
41.4 2680
41.6 2684
41.8 2714
42.0 2722
42.2 2741
42.4 2778
42.6 2761
42.8 2784
43.0 2781

I kept an eye on pressure signs. Everything looked good. Based on my data, should I be looking at 42.4-42.8? If so, where should start the next load at?
Click to expand...
You shot a Ladder. If on a target at 100, you might already have an answer. The notion that relatively flat spots on MV correlate with nodes is somewhat in vogue but not always true. Easily confounded by lack of accuracy in some chrono graphs. The target doesn’t lie.
 
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#21
Seymour Fish said:
You shot a Ladder. If on a target at 100, you might already have an answer. The notion that relatively flat spots on MV correlate with nodes is somewhat in vogue but not always true. Easily confounded by lack of accuracy in some chrono graphs. The target doesn’t lie.
Click to expand...


Ive never seen a ladder show a definitive node shot at 100yds.....Way too close for a ladder. Thats why OCW was created, for those that dont have access to longer ranges for ladders... This is why proper load development is key. Guys that pick a tight group at 100yds instead of picking the group in the center of a node will always show vertical stringing when you shoot it at distance (500yds+). Its hard to get people to understand that picking the tiny group is not how you do load development. You can play with seating depth to tighten your group up AFTER you've picked your Optimal Charge Weight in the center of a node.
 
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#22
If I back off 20 thou from where I was today I know I’m going to start crunching powder on the upper end of 42gn. It shot fine yesterday though. That’s why I added 20 thou to the seating depth today.
 
#23
The tempature is playing some real bad numbers for me today.

I dropped 48 FPS at 41.9 and 49 FPS at 42.5. So my speeds were extremely slow today but they both shot well lol.

I am using H4350 and I have no idea how people claim it to be untouched by the temp changes.
 
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#24
Just to add.. I looked at my groups from today . First round hits from 42.2, 42.3, 42.4, 42.5, 42.6 are touching the POI. Of those groups, 42.4, 42.5 and 42.6 are clustered closest to the POA. All those grains however showed signs of pressure.
 
#25
There is no way you should be crunching powder at 42gr.....I can run 43gr and not crunch powder in Hornady brass.

Have you properly measured distance to your lands with that 140 ELD-M ? What COAL are you hitting the lands?? Typical 6.5cm should be in the 2.835-2.85 range.
 
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#26
padom said:
There is no way you should be crunching powder at 42gr.....I can run 43gr and not crunch powder in Hornady brass.

Have you properly measured distance to your lands with that 140 ELD-M ? What COAL are you hitting the lands?? Typical 6.5cm should be in the 2.835-2.85 range.
Click to expand...

Yeah I went through this in another post but seems like my barrel has a short throat. Pushing hard on the OAL tool push rod I come to a solid stop at 2.72" OAL. I also loaded a bullet in a case and slowly chambered it. I measured where the Sharpie was not scraped off. That method produced 2.68" OAL.
 
#29
If that was me I'd have sent it back and asked why such an unusual, short throat. I cant tell you how many 6.5cm barrels I've had spun up by Keystone and PVA and they all hit the lands in the 2.835- 2.850 range....
 
#30
padom said:
If that was me I'd have sent it back and asked why such an unusual, short throat. I cant tell you how many 6.5cm barrels I've had spun up by Keystone and PVA and they all hit the lands in the 2.835- 2.850 range....
Click to expand...
I shot them an email but haven't gotten a response yet. I plan to give them a call this week anyway. They are 4 hours away from me so I can drop it off versus spending a crazy sum on shipping charges.

Here are the three targets that were closest to POA. As mentioned I'm sure I could have tightened up the groups more had I had feeling in my finger. It was COLD this morning. 5 shot groups. I was also shooting off a bench that is too high for me table top wise. I have to set my Atlas bipod with the legs 45 degs forward to lower it.

IMG_0444.jpgIMG_0445.jpgIMG_0446.jpg
 
#31
You have no way to get proper case capacity and tune seating depth with that short of a throat. Here's one of my 26" Bartlein 6.5cm that contacts the lands at 2.85" COAL.


H4350 / 139 L OCW Test - See how consistent the POI is in relation to POA for the groups. Very wide node on this barrel with this bullet/powder.




Here's my Seating Depth Test after selecting my charge weight
While many groups are very good, see how tight 2.291" Base to Ogive tightens off with no vertical? This is around 2.835" COAL




Berger 140 Hybrids / H4350 OCW - 42.6gr is my load for 140 Hybrids


 
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#36
padom said:
Ive never seen a ladder show a definitive node shot at 100yds.....Way too close for a ladder. Thats why OCW was created, for those that dont have access to longer ranges for ladders... This is why proper load development is key. Guys that pick a tight group at 100yds instead of picking the group in the center of a node will always show vertical stringing when you shoot it at distance (500yds+). Its hard to get people to understand that picking the tiny group is not how you do load development. You can play with seating depth to tighten your group up AFTER you've picked your Optimal Charge Weight in the center of a node.
Click to expand...
We agree it has nothing to do with group size in an OCW. All about the vertical displacement from POA. A ladder at 100, all same aiming point, works well enough to take the center of a decent node straight to 1000. Saves time and $$$. OCW is 3 shots, using the center of each group. Difference is, you move the gun/ position for each set of 3. This is a potential source of error.. you also lose the data on horizontal placement which can tell you something about wind sensitivity early on. Don’t always see it but worth looking for, if hits in a downwind direction. Often the next increment above it is the beginning of your node. Longer string of fire with OCD exposes you to perhaps more conditions, delta barrel heat. Those of us who are weak minded may not hold focus through a whole OCW, another potential variable. Ok, so I will run a 3-shot ladder at 1000 in tenth gr increments. We arrive about the same place
 
#37
As I read this, it sounds to me like muzzle velocity has nothing to do with OCW.

http://optimalchargeweight.embarqspace.com/ocw-overview/4529824091

"With any given bullet and powder combination, there
will be a specific amount of that powder which will
cause the bullet to exit the muzzle at the "friendliest"
portion of the vibration cycle. This does not necessarily
correspond with the tightest velocity figures, however."

"Uniformity of velocity (meaning low extreme spreads of
velocity) are definitely not an indicator of the OCW
zone. We are actually finding that in many cases the
OCW zone does not have the tightest numbers--at least
initially. Fine tuning of the recipe with seating depth
variations and primer changes will improve the velocity
consistency, but simply shooting a succession of
graduated charges over the chronograph and looking for
a tight velocity spread will not lead you to the OCW."
 
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#38
Jammer Six said:
As I read this, it sounds to me like muzzle velocity has nothing to do with OCW.

http://optimalchargeweight.embarqspace.com/ocw-overview/4529824091

"With any given bullet and powder combination, there
will be a specific amount of that powder which will
cause the bullet to exit the muzzle at the "friendliest"
portion of the vibration cycle. This does not necessarily
correspond with the tightest velocity figures, however."

"Uniformity of velocity (meaning low extreme spreads of
velocity) are definitely not an indicator of the OCW
zone. We are actually finding that in many cases the
OCW zone does not have the tightest numbers--at least
initially. Fine tuning of the recipe with seating depth
variations and primer changes will improve the velocity
consistency, but simply shooting a succession of
graduated charges over the chronograph and looking for
a tight velocity spread will not lead you to the OCW."
Click to expand...
Yep. He is alluding to Chris Long’s Barrel Time Theory, where you tune the pressure wave as far away from the muzzle as possible, so bore is tight rather than dilated, at bullet exit. Similar to tuning a header to suck exhaust via sound pulse. Trick is to hit the right barrel time with the MV you want. If you plug exact parameters into quick-load and reverse engineer with proven MV you can often find a correlation. Dan is also alluding to the notion of positive compensation where a slower bullet gets a higher launch angle and intersects with a faster one at some specific range. This is easier to see with a relatively long whippy bbl. you can find Chris’s stuff at The Long Family.com including a chart of several barrel times for each barrel length, diameter playing no role. In discussion with him, he likes to be 1% slower than the chart says, and I find best luck at 2% slower in general. Generally a slow barreltime/Node and a faster one are easily reached, and an even higher one on or over max pressure reachable with some of the newer small primer brass for 308, 260, 6cm, etc. useful to model about where you wand to start and finish s powder set up, the go shoot it, find node, Pt hen chrono best part of it, then back test to see if you are close on a bbl time. Inexact. May need different powder or primer. Good rule for say 300 WM: see a node across 1-1/2 grains powder, or move on to the next one. I don’t buy the notion of flattening of speeds across powder increase as anything but a derivative. It happens but loose correlation
 
#39
Seymour Fish said:
We agree it has nothing to do with group size in an OCW. All about the vertical displacement from POA. A ladder at 100, all same aiming point, works well enough to take the center of a decent node straight to 1000. Saves time and $$$. OCW is 3 shots, using the center of each group. Difference is, you move the gun/ position for each set of 3. This is a potential source of error.. you also lose the data on horizontal placement which can tell you something about wind sensitivity early on. Don’t always see it but worth looking for, if hits in a downwind direction. Often the next increment above it is the beginning of your node. Longer string of fire with OCD exposes you to perhaps more conditions, delta barrel heat. Those of us who are weak minded may not hold focus through a whole OCW, another potential variable. Ok, so I will run a 3-shot ladder at 1000 in tenth gr increments. We arrive about the same place
Click to expand...

This entire statement is wrong, go back and re read how and why a OCW test is done, and if you can’t “focus” through 30 shots... then we have more to talk about
 
#40
I'd say your short throat is due to a worn reamer. I had the same issue. Mine shot very well with factory ammo but when I measured it for 140eld to start reloading it was super short. I contacted my Smith and he pulled dimensions on his reamer and it had quite a bit of wear due to being a 6.5CM reamer in hot demand. He paid to ship it back, fixed it the day it arrived and shipped it back the next day.
 
#41
padom said:
I'd get the barrel fixed or replaced if it was me.
Click to expand...
Also @spooledup
I called Alamo today and spoke to the head gunsmith. I told him what was going on and he said that the shop uses a finish reamer with the throat built in. He said he hasn't had any issues to date with any builds. He also said that more than likely it might be the way I was measuring or the tool but I told him I tried several ways and they all ended up being around the same. They also noted that if I could chamber a factory round then everything was "in spec".
I have some Berger Hybrids coming in and will see what they measure at for grins. They also said I could bring it by and they would take a look at it. I'm 4 hours away but will gladly make the drive.
 
#43
Loaded up a few and here's what I think I'm settling on but I'm not sure about the speed.

41.7gn H4350
2.19" BTO
4x fired Hornady brass w/ ghetto unscientific annealing
210M primers
140gr ELD-M

24" Bartlein barrel with a TBAC Ultra 7 6.5 can

The test target was 5 rounds. Including the pulled one it's about half inch. Not counting it the group is about 0.28". I got 10 rounds through the LabRadar but two did not register. Is this too slow to you guys?

56477547201__D3B4BCA9-ECC0-46BC-897F-9285BC4D70DD.jpgIMG_0531.jpg
 
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