H4831 vs H4831SC "Carolina Load" 6.5CM

[yo-yo]

Hi all -
I was following a recipe for something called a "Carolina Load" for my 6.5CM, except I wanted to use H4831 instead of the H4831SC that was suggested. This is my first time reloading anything, and I don't yet know a lot about various different powders (except from a chart of fast vs. slow burners), but this particular recipe called for 44.3gr of the H4831SC.
I also realized that I bought the wrong bullet for the recipe, but I figured the overall fitment between the two might be minimal, so I proceeded (I have a Hornady 140 gr ELD Match, instead of the suggested 140 gr SST).
Long story short...I cannot fit 44.3 gr of powder in the case, and still install the bullet to COL of 2.800". It's such a compressed load that the bullet cannot be seated that deep and the bullet is mildly damaged when I attempt to seat it at that COL.
Is the physical shape of the power's granule quite different between these two powders? Is the Short Cut powder much smaller in size? I can't find a lot of information about the powder differences.
Thanks!

 

[straightshooter1]

Yes, the Short Cut is smaller in size, allowing you to get more of it into a particular case volume than the regular cut. With H4831SC, you should be able to get at 44.3 grs into your case's COAL of 2.800" without much, if any, powder compression (depending on your particular case volume of the brass you're using).

 

[yo-yo]

Yes, the Short Cut is smaller in size, allowing you to get more of it into a particular case volume than the regular cut. With H4831SC, you should be able to get at 44.3 grs into your case's COAL of 2.800" without much, if any, powder compression (depending on your particular case volume of the brass you're using).

Interesting. Thanks!
Crazy…is there a place I can better research detailed powder attributes to better understand how all these powders differ? I don’t see a lot of technical data on seller sites.

 

[supercorndogs]

Looks like i was using 45.7 h4831sc in hornady brass with the 143eld at around 2.85. I don't rmeber if I was crunching. Might have been too hot. It was my MO at the time. LOL. I switch to h4350 since. What is your jump at 2.8 oal?

 

[whatsupdoc]

H4831 is a marginal powder for the 6.5 creed and compressed loads will usually cause extreme seating depth variation
of the bullet. Compressed loads provide zero benefit.

 

[straightshooter1]

Looks like i was using 45.7 h4831sc in hornady brass with the 143eld at around 2.85. I don't rmeber if I was crunching. Might have been too hot. It was my MO at the time. LOL. I switch to h4350 since. What is your jump at 2.8 oal?

Hmmm??? Why do you ask about jump? Are you assuming his chamber's freebore is the same as yours or that the lands is the same distance after throat erosion?

 

[supercorndogs]

I ask because he didn't provide that information and it's important how much powder he can for in the case. I would expect him to be able to run longer than 2.8 because both my 6.5 creed barrels were around .02 off at 2.85 and I see a lot of others running 2.84-2.9 range.

I liked h4831sc in my 26" barrel but not so much in my 21". Ended up really liking varget and 123s. I was shooting them both when h4350 was unavailable.

 

[straightshooter1]

I ask because he didn't provide that information and it's important how much powder he can for in the case. I would expect him to be able to run longer than 2.8 because both my 6.5 creed barrels were around .02 off at 2.85 and I see a lot of others running 2.84-2.9 range.

I liked h4831sc in my 26" barrel but not so much in my 21". Ended up really liking varget and 123s. I was shooting them both when h4350 was unavailable.

I have little doubt that he can go longer, like at least out to mag length.

I would have asked about distance to lands rather than jump since amount of jump could be any length depending on a chambers freebore and throat erosion. Like, .020 off means 2.850 for you, but could mean 2.890 for me. This focus on jump tends to be confusing to new reloaders in trying to determine actual seating depths being referred to when realizing that chambers are simply not likely to be the same size.

 

[supercorndogs]

He said he was at 2.8 so his jump plus 2.8 would have told how much room he had.

I am not understanding I though your jump was your distance to the lands.

 

[BobinNC]

Hi all -
I was following a recipe for something called a "Carolina Load" for my 6.5CM, except I wanted to use H4831 instead of the H4831SC that was suggested. This is my first time reloading anything, and I don't yet know a lot about various different powders (except from a chart of fast vs. slow burners), but this particular recipe called for 44.3gr of the H4831SC.
I also realized that I bought the wrong bullet for the recipe, but I figured the overall fitment between the two might be minimal, so I proceeded (I have a Hornady 140 gr ELD Match, instead of the suggested 140 gr SST).
Long story short...I cannot fit 44.3 gr of powder in the case, and still install the bullet to COL of 2.800". It's such a compressed load that the bullet cannot be seated that deep and the bullet is mildly damaged when I attempt to seat it at that COL.
Is the physical shape of the power's granule quite different between these two powders? Is the Short Cut powder much smaller in size? I can't find a lot of information about the powder differences.
Thanks!

Without getting too preachy I see some flaws in your reloading approach:

Never, ever use anybody's "recipe" without working up to it from below, for 'your' rifle with 'your' components.

Number two, your initial coal should consider the following:

The longest coal that will fit and feed from your mag; that one, does not jam the bullet into your lands; and two, keeps at least one caliber (in your case .264") of bearing surface inside your case neck. (the boat tail, if any, doesn't count).

Note: Longer bullet seating means more room for powder in your case. This may or may not be a good thing until you try it.

What someone else did, with their rifle and their load, is irrelevant until you test first in your rifle, using your components, and worked up from below.

 

[straightshooter1]

He said he was at 2.8 so his jump plus 2.8 would have told how much room he had.

I am not understanding I though your jump was your distance to the lands.

Jump is distance FROM the lands, not to the lands.

When I measure all the way "to" the lands that number for CBTO is 2.278. Then when I'm .020 "off" or from the lands, or the amount of jump, the CBTO measurement is 2.258.

I guess one can think of it as the distance your jumping "to" the lands. But, that's also how far you are "from" the lands.

Amount of jump (like .020) just doesn't tell anything about the CBTO or COAL of the cartridge because of differences in chamber specs.

 

[supercorndogs]

My distance from Denver is exactly the same as my distance to Denver. One can think of it that way because it is the same thing.

 

[straightshooter1]

My distance from Denver is exactly the same as my distance to Denver. One can think of it that way because it is the same thing.

Knowing the distance to or from the lands tells you what about a cartridges CBTO or COAL?

 

[supercorndogs]

Knowing the distance to or from the lands tells you what about a cartridges CBTO or COAL?

He is loading at 2.8. If he is .06 off. He can seat 2.85 and be around .01 off.

 

[straightshooter1]

He is loading at 2.8. If he is .06 off. He can seat 2.85 and be around .01 off.

OK, I see. You're just guessing "if" he's .060 off when loading to COAL of 2.800.

 

[supercorndogs]

OK, I see. You're just guessing "if" he's .060 off when loading to COAL of 2.800.

No, that is what's called a "hypothetical" to help some argumentative fucker understand basic math and english. What the fuck are you even trying to argue about. 4 posts about wheather it should be to the lands or from the lands.

New reloaded have trouble because people want to argue about stupid inane shit in their threads instead of helping them. Guess what, if a bullet jumps .06 to the lands it was .06 from the lands. The only diffrence is which object the preposition was refering to.

I dont know what the OP's jump is. Thats why I asked him you pedantic cheese weasel.

If you want to argue about it more go find an English major or start a bear pit thread.

 

[yo-yo]

Looks like i was using 45.7 h4831sc in hornady brass with the 143eld at around 2.85. I don't rmeber if I was crunching. Might have been too hot. It was my MO at the time. LOL. I switch to h4350 since. What is your jump at 2.8 oal?

Interesting. OK. I was only able to get 41.4 gr in the case, without "crunching". I was shocked how bad the bullets were being damaged with that much in the case. I don't know how much room I have left yet. I haven't tried measuring that "jump". I've been reading about that though. How does that work? Is the goal to get the bullet as close to the lands as possible, without causing issues?

 

[yo-yo]

I ask because he didn't provide that information and it's important how much powder he can for in the case. I would expect him to be able to run longer than 2.8 because both my 6.5 creed barrels were around .02 off at 2.85 and I see a lot of others running 2.84-2.9 range.

I liked h4831sc in my 26" barrel but not so much in my 21". Ended up really liking varget and 123s. I was shooting them both when h4350 was unavailable.

I have a 26" barrel too, and the original recipe I read about didn't disclose the barrel length, but there were a lot of people agreeing to the results they experienced as well. I can probably run longer, I just haven't inspected that yet.

 

[yo-yo]

Without getting too preachy I see some flaws in your reloading approach:

Never, ever use anybody's "recipe" without working up to it from below, for 'your' rifle with 'your' components.

Number two, your initial coal should consider the following:

The longest coal that will fit and feed from your mag; that one, does not jam the bullet into your lands; and two, keeps at least one caliber (in your case .264") of bearing surface inside your case neck. (the boat tail, if any, doesn't count).

Note: Longer bullet seating means more room for powder in your case. This may or may not be a good thing until you try it.

What someone else did, with their rifle and their load, is irrelevant until you test first in your rifle, using your components, and worked up from below.

Gotcha, thanks for the thoughts here. It made sense for me to start fro some reference point, based on several other accounts of the success, but I get your meaning. This is literally the first time I've ever done this, so other than random books with other random fitments, I thought I'd try this.
How does one go about measuring the distance from the bullet to the lands? Do you load a round in a engage the bolt and just see if the bullet hits the lands, or is there some kind of tool that can do this properly?

 

[yo-yo]

He is loading at 2.8. If he is .06 off. He can seat 2.85 and be around .01 off.

I'll have to figure out how to measure this distance. I know these loads are a bit longer than the other factory loads I measured. Also, the cases I bought (new) (Lapua) are a bit shorter than the once fired factory loads, so I'll have to pay attention to that. Once I figure out how long the load "ca be", I'll go from there. I might be able to use the H4831 (old long cut) with a little longer COL. Right now, I'm just hand feeding each shot, so I can mess a round a bit with the longest that can fit.

 

[6.5SH]

Gotcha, thanks for the thoughts here. It made sense for me to start fro some reference point, based on several other accounts of the success, but I get your meaning. This is literally the first time I've ever done this, so other than random books with other random fitments, I thought I'd try this.
How does one go about measuring the distance from the bullet to the lands? Do you load a round in a engage the bolt and just see if the bullet hits the lands, or is there some kind of tool that can do this properly?

Lock‑N‑Load® O.A.L. Gauges & Modified Cases - Hornady Manufacturing, Inc

Lock-N-Load® O.A.L. Gauges Regulating seating depth and the resulting jump to the rifling is widely regarded as fundamental to improved accuracy. A few thousandths of an inch change between the bullet and the rifling can make the difference betw...

www.hornady.com

There are other variations of the tool from different vendors

 

[yo-yo]

Jump is distance FROM the lands, not to the lands.

When I measure all the way "to" the lands that number for CBTO is 2.278. Then when I'm .020 "off" or from the lands, or the amount of jump, the CBTO measurement is 2.258.

I guess one can think of it as the distance your jumping "to" the lands. But, that's also how far you are "from" the lands.

Amount of jump (like .020) just doesn't tell anything about the CBTO or COAL of the cartridge because of differences in chamber specs.

If I'm understanding this correctly...there is a measurement that allow the COL to be "at the lands" and this would be the longest allowable length of the cartridge (even if that doesn't fit in the magazine and it does satisfy your minimum seating depth of "one caliber" of the body of the bullet into the case - not including the boat tail). Is there a term used to describe that distance in the rifle, based on all the chamber characteristics? That would see to me to be a place to start talking about how long a cartridge could be, and working back from there. I'm just thinking out loud here though.

 

[yo-yo]

Lock‑N‑Load® O.A.L. Gauges & Modified Cases - Hornady Manufacturing, Inc

Lock-N-Load® O.A.L. Gauges Regulating seating depth and the resulting jump to the rifling is widely regarded as fundamental to improved accuracy. A few thousandths of an inch change between the bullet and the rifling can make the difference betw...

www.hornady.com

There are other variations of the tool from different vendors

Oh, great! Thanks!!!

 

[supercorndogs]

The cases are important too. Lapua is going to hold less than my Hornady brass does. Sometimes the eld bullets don't jive well with the seater in the die. Then the seater pushes on the tip and damages bullets. If you are seeing rings its not pushing on the tip.

 

[19Scout77]

Vibrate your loading block a little and that powder will settle and provide more room.

 

[supercorndogs]

There are a lot threads about measuring. Hornady has a tool with modified case. I have seen people say they use a fired case and locktite. Or a case with split neck.

I would expect if they made the load you are kind of replicating in hornady brass you will probably be around 1-1.5g less powder to reach the same velocity in Lapua. Also the 140eld is a very diffrent bullet from the 140sst. I would load and shoot an ocw or at least a chrono ladder to see where you are velocity vs charge.

 

[Landon4]

I think you need to do some more research on the measurement part of reloading, and yes there are several tools that would help you in this case. Hornady makes an oal tool and a tool to put on your calipers to check your cbto, these would be helpful before you stick a bullet or worse have something malfunction and injure yourself.

 

[supercorndogs]

Vibrate your loading block a little and that powder will settle and provide more room.

Longer drop tube can help too. Lapua brass is thick though.

 

[johnnyvw]

So you used a recipe, but with different powder and bullet. So you really didn't follow a recipe (which as others have stated isn't the greatest idea without "working up" to the specified load).

Why not start with a load that either Hornady or Hodgdon recommends?

 

[Landon4]

So you used a recipe, but with different powder and bullet. So you really didn't follow a recipe (which as others have stated isn't the greatest idea without "working up" to the specified load).

Why not start with a load that either Hornady or Hodgdon recommends?

Probably using different brass also as he’s using lapua which doesn’t have the same case capacity, but he didn’t specify what was used in the original load he was copying.

 

[6.5SH]

Yikes on the thread and most of the information given where this "recipe" originated:

https://forum.accurateshooter.com/threads/the-secret-6-5-carolina-load.3958973/

There are a few valid posts in there that give some good info, but the opener and following posts from that person are just trash.

Not trying to beat up on you OP, you don't know what you don't know. The best advice I can give you is start with "book" loads and the listed C.O.L. for a given bullet in that cartridge. When "A" particular component isn't available cross reference the load data between those vendors to see how much the load varies, if it looks similar it is likely safe to try below max and work your way up.

https://hodgdonreloading.com/rldc/?t=1

 

[yo-yo]

The cases are important too. Lapua is going to hold less than my Hornady brass does. Sometimes the eld bullets don't jive well with the seater in the die. Then the seater pushes on the tip and damages bullets. If you are seeing rings its not pushing on the tip.

Oh interesting. Ok. Yeah, I had an issue with the searing die early on and Forster sent me some new parts. What are “rings”? I was seeing a damage ring around the circumference of the bullet, when there was too much powder in them. Once I reduced the powder weight, that problem ceased.

 

[yo-yo]

Vibrate your loading block a little and that powder will settle and provide more room.

thanks. Good ideas. I did shake it a bit to try and help, but it was far too much. . I also picked up some H4831SC yesterday. I’ll play with that too, to see how it differed.

 

[yo-yo]

There are a lot threads about measuring. Hornady has a tool with modified case. I have seen people say they use a fired case and locktite. Or a case with split neck.

I would expect if they made the load you are kind of replicating in hornady brass you will probably be around 1-1.5g less powder to reach the same velocity in Lapua. Also the 140eld is a very diffrent bullet from the 140sst. I would load and shoot an ocw or at least a chrono ladder to see where you are velocity vs charge.

Ok. I’ll do some homework on the topic. Yeah, I didn’t see a lot of marketing on the bullet differences. Certainly not in the box in the store. And hornady’s website is a bit difficult to navigate, and has some repetitive listings for same products that confused me. I’ve never studied bullets, so I’m just learning. Looks like the SST is more for large would sites. I’m only target shooting, so I don’t really care about that. I have the ELD Max bullets and both powders now, so I’ll play around with different variations from what I have to work with, and see what happens. The books had similar characteristics of bullet style and COL, but none are showing the use of this powder for the 6.5CM. I also would love to see something better than a simple color chart of burn speeds if the powders. Is there any numerical value attached to these burn rates? Relating their burn speeds in order of fast to slow, doesn’t give me a lot to go on.

 

[ma smith]

This whole thread is wild.

I'm no reloading genius by any stretch.
But here's a couple observations...

One needs mathematically consistent shape+volume+energy to get mathmatically equal pressure...so no changing brass volumes, no changing powders/powder-cuts, no changing bullet shape, no changing chamber-reamer-specs, etc

You therefore need to undestand/rely on process...

Reloading 101
step 1: RTFM
step 2: Follow a proper reloading process
step 3: Profit

 

[yo-yo]

So you used a recipe, but with different powder and bullet. So you really didn't follow a recipe (which as others have stated isn't the greatest idea without "working up" to the specified load).

Why not start with a load that either Hornady or Hodgdon recommends?

I didn’t realize the bullets were that different. There aren’t any 6.5CM SST’s laying around here, so decided that was the next best thing I could try. All the research I did on powders, just said they “performed” about the same. Nothing relating to the granule size (not sure what the proper term is here) and how much might fit into the case. I adapted with less powder until I could get some SC in my hands. I’m generally open to user-based feedback as relational information. I will certainly continue as necessary. The books showed very similar powder volume and COL, but generally fail yo give good info on powder characteristics.

 

[yo-yo]

This whole thread is wild.

One needs mathematically consistent shape+volume+energy to get mathmatically equal pressure...so no changing brass volumes, no changing powders/powder-cuts, no changing bullet shape, no changing chamber-reamer-specs, etc

You therefore need to undestand/rely on process...

Reloading 101
step 1: RTFM
step 2: Follow a proper reloading process
step 3: Profit

I wasn’t looking for repeatability. Just data. I can track changes between loads well enough. I’m starting from zero, other than factory load data (which omits any powder info) and user-based recommendations.
Where is there a manual?
How does a rookie determine a process is “proper”?
What do you mean “profit”?

 

[ma smith]

I wasn’t looking for repeatability. Just data. I can track changes between loads well enough. I’m starting from zero, other than factory load data (which omits any powder info) and user-based recommendations.
Where is there a manual?
How does a rookie determine a process is “proper”?
What do you mean “profit”?

I would disagree, and say you are looking for 100% repeatability, you just are completely not quite sure about what you are doing.

The variable you are controlling in reloading is chamber pressure. This needs to be 100% below the limit where your rifle blows up in your face.

Therefore, you need to undestand the basics of pressure equation.

A "good load" or reciple only works when the critical variables of the pressure equation (ie the limits) are in line with the original formula.

A good reloading process tests for each variation from known good data in a structred way.

Therefore you can modify the original recipe/formula without getting out of balance.

 

[straightshooter1]

If I'm understanding this correctly...there is a measurement that allow the COL to be "at the lands" and this would be the longest allowable length of the cartridge (even if that doesn't fit in the magazine and it does satisfy your minimum seating depth of "one caliber" of the body of the bullet into the case - not including the boat tail). Is there a term used to describe that distance in the rifle, based on all the chamber characteristics? That would see to me to be a place to start talking about how long a cartridge could be, and working back from there. I'm just thinking out loud here though.

There's no specific term, none that I'm aware of anyway, that refers to what you describe that includes the "one caliber" of the bearing surface into the case/neck.

That "one caliber" is typically a safe way to load so that recoil doesn't move the bullets in the necks as they sit in the magazine about to be fed. And even with that amount or more of bearing surface being held, how effective that is in that way depends on the amount of "neck tension" and interference a reloader builds into the neck. Also, if there's not enough bearing surface being held, the feeding from a mag can change the bullets concentricity when it engages the feeding ramp.

It's not unusual for some reloaders to load long with less than that "one caliber", especially when hand loading the cartridges rather than feeding from a mag. Like for some reloaders, it's not much of an issue as they'll hand load a cartridge so long that it does more than just touch the lands, but will have something like .020 of jam into the lands (not something I'd recommend for a hunting gun or someone that doesn't really know what they're doing).

It's always good to know where your lands is relative to your cartridge within you're particular chamber, mainly for making a decision on a starting point for a seating depth, though rarely a thing to be concerned with at all if you're reloading to mag length for mag feeding. That distance to touching the lands is a CBTO (Cartridge Base To Ogive) measured with your particular comparator. The COAL (Cartridge Over All Length) isn't typically something to focus on, but when conveying your cartridge configuration, it's better to convey COAL rather than CBTO since the other reloader you're communicating with will most likely be using a comparator that's different from the one you're using. Though you, at some point, may have established a CBTO that gives you a particular "jump", the COAL will better convey to someone else your cartridge configuration. And you don't want to just tell anyone what your "jump" is, as that too has no real meaning to someone else, unless their chamber is exactly the same size as yours (different barrel have different length chambers, even those produced with the same reamer depending on how much throat erosion has occurred over a number of firings).

If someone tells me their COAL and the bullet they're using for the particular cartridge, I can then determine how that cartridge fits in my camber by loading a dummy round with that bullet at that COAL (yes, bullet OAL's do vary some because of meplat variations). Then I measure with my own comparator (my comparator can be something like .067" different) to see what CBTO that gives me, and that will tell me how much jump that particular cartridge configuration has in my particular chamber since I already know the distance to my lands having used my same comparator.

Amount of jump is not as important as seating depth (how far the base of the bullet seats into the case). Certainly, changing seating depth changes the amount of jump. But throat erosion also changes jump. Once you find a seating depth that works, you really want to keep it there rather than "chasing the lands" as keeping that seating depth that works will keep working as the jump increases due to throat erosion (for quite a while anyway).

. . . hope this long winded reply helps.

 

[straightshooter1]

I didn’t realize the bullets were that different. There aren’t any 6.5CM SST’s laying around here, so decided that was the next best thing I could try. All the research I did on powders, just said they “performed” about the same. Nothing relating to the granule size (not sure what the proper term is here) and how much might fit into the case. I adapted with less powder until I could get some SC in my hands. I’m generally open to user-based feedback as relational information. I will certainly continue as necessary. The books showed very similar powder volume and COL, but generally fail yo give good info on powder characteristics.

Yup,
Bullets, Powder, Brass and Primers are all different. Finding the right combination is the challenge.

For someone just starting out, it's always best to go by what successful shooters and reloaders find working well in the cartridge you use, particularly when it comes to choosing a powder. It also can save you time and money if you can find an experienced mentor where you shoot at that's willing to help you through the learning curve.

A powder doesn't always burn at the same rate as things like temperature its at when ignited and its moisture content. Have the powder exposed to very dry atmosphere and it'll dry out and burn faster. Likewise, being exposed to very humid atmosphere, it can gain moisture and burn slower. These are two of several factors effecting how a powder will burn. There can be variations from one lot of powder to the next from the same manufacturer. So, the best thing to do is go by velocity you record for the charge weight you've used.

I have the software QuickLoad that get me into the ballpark for how the powder if performing and what other powder might work. It has a database for most powders and gives a default burn rate that I'll adjust according to my recorded velocities. It's a very handy tool that saves me time and components when trying to find a decent combination that I'll need to fine tune. There's quite a learning curve to using the tool well.

You might want to download a tool similar to QuickLoad called Gordon's Reloading Tool (see pic at the very bottom). It too has quite a learning curve, but since it's a free download, it's something you can play with that'll probably help you learn some things too.

I don't have all the input data for your particular set up, but here some info/example that should give you some idea about the powder you're about to use. It's not fine tuned for you, so don't take the info as something you can count on:

This is what Gordons Reloading Tool looks like:

 

[johnnyvw]

Probably using different brass also as he’s using lapua which doesn’t have the same case capacity, but he didn’t specify what was used in the original load he was copying.

Re-read the first post, he laid out exactly what the recipe called for and what he did different

Edit: You're talking just the brass, right? Overlooked that....oops, sorry

 

[johnnyvw]

BTW, I checked the Hornady manual, the 140gr SST COAL is listed as 2.690", compared to the 140gr ELDM at 2.800. I would have to look further but that tells me the SST is a shorter bullet OAL, so if you load it out at 2.800 then you won't have a compressed load. Then the question is where does the ogive sit relative to the lands IN YOUR GUN.

This is why you have to have the proper data and not just switch out components willy-nilly.

 

[roostercogburn98]

A Carolina load??? For fucks sake, is your rifle squatted as well?

 

[Landon4]

BTW, I checked the Hornady manual, the 140gr SST COAL is listed as 2.690", compared to the 140gr ELDM at 2.800. I would have to look further but that tells me the SST is a shorter bullet OAL, so if you load it out at 2.800 then you won't have a compressed load. Then the question is where does the ogive sit relative to the lands IN YOUR GUN.

This is why you have to have the proper data and not just switch out components willy-nilly.

According to Jbm the sst bullet is slightly longer than the eld, only by .036

 

[johnnyvw]

That's interesting. Have to wonder about the BTO length then for the COAL to be so much shorter. Lot's of questions here, in my mind

 

[Landon4]

Yeah I figured the eld would be longer with the issues he was having.

 

[yo-yo]

I would disagree, and say you are looking for 100% repeatability, you just are completely not quite sure about what you are doing.

The variable you are controlling in reloading is chamber pressure. This needs to be 100% below the limit where your rifle blows up in your face.

Therefore, you need to undestand the basics of pressure equation.

A "good load" or reciple only works when the critical variables of the pressure equation (ie the limits) are in line with the original formula.

A good reloading process tests for each variation from known good data in a structred way.

Therefore you can modify the original recipe/formula without getting out of balance.

I just meant the purpose of choosing this recipe was to get a data point. There was no other starting point. There isn't *any* use of H4831 or H4831SC in any of the books for 6.5CM. Also, all the feedback I received about those powders was "they should burn very similarly", so I think the "data point" was a reasonable goal.

 

[yo-yo]

There's no specific term, none that I'm aware of anyway, that refers to what you describe that includes the "one caliber" of the bearing surface into the case/neck.

Amount of jump is not as important as seating depth (how far the base of the bullet seats into the case). Certainly, changing seating depth changes the amount of jump. But throat erosion also changes jump. Once you find a seating depth that works, you really want to keep it there rather than "chasing the lands" as keeping that seating depth that works will keep working as the jump increases due to throat erosion (for quite a while anyway).

. . . hope this long winded reply helps.

Thanks for the reply! I will digest this a little bit and do some vocabulary homework. Thank you!
I'm looking into some of the tools I can use to make these measurements, but I'm cringing looking at how accurate and repeatable these tools are. I'm an experienced engine builder, so I usually look for much better tool precision.
I'll study this a bit more!
Thanks!

 

[yo-yo]

Yup,
Bullets, Powder, Brass and Primers are all different. Finding the right combination is the challenge.

For someone just starting out, it's always best to go by what successful shooters and reloaders find working well in the cartridge you use, particularly when it comes to choosing a powder. It also can save you time and money if you can find an experienced mentor where you shoot at that's willing to help you through the learning curve.

I don't have all the input data for your particular set up, but here some info/example that should give you some idea about the powder you're about to use. It's not fine tuned for you, so don't take the info as something you can count on:


This is what Gordons Reloading Tool looks like:

Interesting! I didn't realize there was a software program that cataloged this data. I'll look into those!
I understand that burn rates my vary with environmental conditions, but I assume since there is a table "from fastest to slowest" burns, there must be some documented burn rate for a given set of conditions (temp, humidity, atmos pressure, etc.). That's all I was looking for - for a base understanding of how the H4831 I have compared to other powders that were in the books I have. We have LOTS and LOTS of the H4831, so I wanted to use that, if it was similar to the H4831SC that was called for in the Carolina Load.

I do have a chronograph so I can fine tune into the power with that. Thank you for the suggestions!

 

[yo-yo]

BTW, I checked the Hornady manual, the 140gr SST COAL is listed as 2.690", compared to the 140gr ELDM at 2.800. I would have to look further but that tells me the SST is a shorter bullet OAL, so if you load it out at 2.800 then you won't have a compressed load. Then the question is where does the ogive sit relative to the lands IN YOUR GUN.

This is why you have to have the proper data and not just switch out components willy-nilly.

Yeah, I didn't yet look into the overall specs on the SST bullet, and I wonder if the length dimensions of the bullet play a role in the compress or not compressed load.
I can make the proper measurements, other than I'm not impressed with the tools for this...
I just needed some feedback on the situation, as I was suspecting the issue was the powder. In all the research I did, nobody states the physical dimensions of the powder nodules (whatever they are called), so I couldn't verify this.