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Considering......

1. I didn't even own a caliper for many years while reloading 1000s and 1000s of rounds (both rifle and pistol rounds).

2. A single hair has a diameter of about 0.0047 inches. So, 0.005 inches.....sorry, I'm not overly concerned.

3. I've been lucky (I guess). Or blessed.

The BIGGEST safety factor (for ME)......is about following the recipe in the reloading manual. Most manuals will say to use the "starting load" or it'll say to reduce by x% and slowly work your way up to the maximum (if you're going that far). While also watching for the "signs" of overpressure.

Anyway.......getting back to precise measurements with your caliper. You'll also note that bullets themselves can vary. One brand to the next. Or even within a production lot # and/or product line. Especially with hollow point bullets. Then, things can also change from time to time. Call it tweaking the specs a bit. Sometimes, it's even/also a matter of quality control.

YES....consistency in your ammo makes for better accuracy. But, there is a limit. And many times it's due to many other factors (besides just your ammo).

Good luck with your new hobby/endeavor.

Aloha, Mark

PS.......
LOL......I used my M-1 eyeball for these.

View attachment 1280675

9mm reloads.
Yup....it passed the plop test. BUT, But, but......it didn't feed from the magazine worth a dam.

So.....make sure that your ammo will also feed from the magazine, chamber, fire, extract and eject before you call, "SUCCESS".
thank you.
 
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I apologize.

I make my share of mistakes too. LOL....WHY was I even looking at load data for the 7.62x39mm and not the 300 Blackout (aka : 300 AAC Blackout or 7.62x35)?

Yeah, just typing that. Gave me a partial answer to my "problem" with/about just thinking. LOL.

Aloha, Mark

PS.....I guess I should also point out.....the fact that my el-cheap-o RCBS dial caliper does readings in inches. While my even cheaper HF caliper will do inches and mm, with just a push of a button.

Progress.
 
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Then you will be fine. Variations in seating depth can affect accuracy but as long as the COAL is withing saami spec they are safe using published load data, starting at minimum.
thank you it was answer i was looking for. i knew saami COAL was 1.780 - 2.260. i do know these have a COAL of 1.90-1.91 variation due to tweaking seating depth on my die..
I am confident on my measurements and my process. was just double checking that variation.
have them kinda grouped to test each. MAG FEED CHAMBER CYCLE ETC
@Pepe-lepew gave a measurement of Vihtavuori data and if i loaded that length i am not sure bullet is deep enough honestly.I think half the ribs on the bullet would be above the case mouth. tho i could be wrong for sure.
 
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I apologize.

I make my share of mistakes too. LOL....WHY was I even looking at load data for the 7.62x39mm and not the 300 Blackout (aka : 300 AAC Blackout or 7.62x35)?

Yeah, just typing that. Gave me a partial answer to my "problem" with/about just thinking. LOL.

Aloha, Mark

PS.....I guess I should also point out.....the fact that my el-cheap-o RCBS dial caliper does readings in inches. While my even cheaper HF caliper will do inches and mm, with just a push of a button.

Progress.
my minimum case length is at 1.350 where i got 35 in my head then typed 35mm lol.
 
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I assume you mean.....

"ribs" on the bullet = cannelure (3 bullets on the right)

1663942908073.png

and the cannelure concept/word.....could/can/is also used for cases too.

1663942237345.png

According to Wikipedia.

In modern bullets, such as the 7.62 illustrated here, the cannelure is pressed into the circumference of the bullet to provide a strong purchase for the mouth of the cartridge case when it is crimped onto that cannelure. This is done to prevent the bullet from moving either forward or backward in the case.
in addition.....

In cartridges, the cannelure is a band pressed into the case which helps prevent cartridge setback when the case mouth is properly crimped onto the cannelure. Bullet setback of .1" can increase pressure beyond safe limits and possibly cause a catastrophic failure
I look at the cannelure "as a suggestion" (not written in stone) for bullet placement within the case. And, since bullets will vary.....I don't pay attention to the cannelure on my brass cases. You'll probably notice them on .357 magnum cases (not so often with .38 special cases).

Aloha, Mark
 
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Welcome to loading. I’d say 5 thousandths is more than an acceptable margin of error.

More than enough here will be glad to assist you in your endeavors. Don’t feel bad asking questions you may think are novice based.

Don’t be afraid of screwing up. Yes you can blow off a finger, maybe. Likely it will be simple things you overlook.

For instance, after reloading for some 15 or so years, the other day I went to load a string of 5x5 6mm ARC ladders. I usually keep the cases in a loading block and charge every case separately before seating a bullet. Wasn’t paying the greatest attention otherwise I’d might have noticed how low the charges sat in the cases. After finishing charging each case, yes all 25, I lifted the first to seat a bullet and powder comes streaming out of the bottom. Yep, I placed 25 cases into the block and totally skipped the step where you add primers to the case!!! I was able to save most of the powder but lost a god bit and my loading block was in need of a good cleaning.
 
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I assume you mean.....

"ribs" on the bullet = cannelure (3 bullets on the right)

View attachment 1280887

and the cannelure concept/word.....could/can/is also used for cases too.

View attachment 1280886

According to Wikipedia.


in addition.....


I look at the cannelure "as a suggestion" (not written in stone) for bullet placement within the case. And, since bullets will vary.....I don't pay attention to the cannelure on my brass cases. You'll probably notice them on .357 magnum cases (not so often with .38 special cases).

Aloha, Mark
not sure these are cannelure. here is the image of lapua 123 gr but has 1 more groove

or more like this
 
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I assume you mean.....

"ribs" on the bullet = cannelure (3 bullets on the right)

View attachment 1280887

and the cannelure concept/word.....could/can/is also used for cases too.

View attachment 1280886

According to Wikipedia.


in addition.....


I look at the cannelure "as a suggestion" (not written in stone) for bullet placement within the case. And, since bullets will vary.....I don't pay attention to the cannelure on my brass cases. You'll probably notice them on .357 magnum cases (not so often with .38 special cases).

Aloha, Mark

I assume you mean.....

"ribs" on the bullet = cannelure (3 bullets on the right)

View attachment 1280887

and the cannelure concept/word.....could/can/is also used for cases too.

View attachment 1280886

According to Wikipedia.


in addition.....


I look at the cannelure "as a suggestion" (not written in stone) for bullet placement within the case. And, since bullets will vary.....I don't pay attention to the cannelure on my brass cases. You'll probably notice them on .357 magnum cases (not so often with .38 special cases).

Aloha, Mark
here is my projectile and a finished case minus primer and powder
these run between min1.90-1.91max various in between due to my first ever loading and setting up the die.
I suppose i can not set as deep but should I?
Should it be backed out to next grove? that would possibly get me over spec on COAL.
All help is much appreciated

20220923_103938.jpg
 
.005" is nothing to worry about, heck a normal bullet can vary in profile resulting in .005” fairly often. Lapua's are pretty uniform though so I wouldn't expect much of that but will happen every so often I'm sure.
.010” might start to concern me. Depending on the load and load volume. Once you get into the .0625” territory (deeper/shorter) then I'd be concerned for sure. A load this much shorter (depending on the case) can increase pressure as much as 10k psi chamber pressure.

Now.. If its .005" further out absolutely no sweat. Further out should lower pressure until maybe if your jambing the bullet in the lands which would probably wouldn't fit in a mag. Jamming the bullet in the lands gives no bullet jump and from what I understand can cause a sharper spike in pressure because the bullet doesn't have any room to slide out with minimal resistance while pressure slowly builds up. Think of diving into water vs falling on concrete then adding pressure on top of that.
but generally I'd much rather them be slightly longer than shorter. Hopefully this helps.
 
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.005" is nothing to worry about, heck a normal bullet can vary in profile resulting in .005” fairly often. Lapua's are pretty uniform though so I wouldn't expect much of that but will happen every so often I'm sure.
.010” might start to concern me. Depending on the load and load volume. Once you get into the .0625” territory (deeper/shorter) then I'd be concerned for sure. A load this much shorter (depending on the case) can increase pressure as much as 10k psi chamber pressure.

Now.. If its .005" further out absolutely no sweat. Further out should lower pressure until maybe if your jambing the bullet in the lands which would probably wouldn't fit in a mag. Jamming the bullet in the lands gives no bullet jump and from what I understand can cause a sharper spike in pressure because the bullet doesn't have any room to slide out with minimal resistance while pressure slowly builds up. Think of diving into water vs falling on concrete then adding pressure on top of that.
but generally I'd much rather them be slightly longer than shorter. Hopefully this helps.
Understood, my new dilemma, @Pepe-lepew gave me a load data from Vihtavuori. saying COAL 1.976?
im between min 1.90-1.915 on this batch i have
in this pic you see my load and lapua lead next to it if i pull depth back out to 1.976 thats 60 thnds longer i feel that bullet will not be deep enough? Or by chance am i way overseating this?
any help is greatly apprciated

20220923_103938.jpg
 
You should also be able to check for jam by putting sharpie all over your bullet loading it into the chamber normally and then extract it, if the bullet sticks in the lands and pours powder everywhere (congrats ;)) its too long. OR it will usually put some small marks showing bare metal around the bullet and then you know its touching the lands.
For me, I like to know what my jam length is before starting loading. So I know how much room I have to play with. Most folks don't care, and for shorter bullets like 55gr fmj's people just load them to length to where the cannelure groves is at the case mouth crimp it and go and call it good. If your loading for accuracy with longer heavier bullets, then you might want to play with seating depth for optimal accuracy.
 
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You should also be able to check for jam by putting sharpie all over your bullet loading it into the chamber normally and then extract it, if the bullet sticks in the lands and pours powder everywhere (congrats ;)) its too long. OR it will usually put some small marks showing bare metal around the bullet and then you know its touching the lands.
For me, I like to know what my jam length is before starting loading. So I know how much room I have to play with. Most folks don't care, and for shorter bullets like 55gr fmj's people just load them to length to where the cannelure groves is at the case mouth crimp it and go and call it good. If your loading for accuracy with longer heavier bullets, then you might want to play with seating depth for optimal accuracy.
my worry now is am i too deep on seat? just optically it looks right? and within saami spec?
vihtavuori load data showed case length @ 1.362" mine are 1.350 min so im off on that data by .012 roughly shorter.
with that said would my COAL should be around 1.964 vs the 1.976 per vihtavuori data?
 
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Understood, my new dilemma, @Pepe-lepew gave me a load data from Vihtavuori. saying COAL 1.976?
im between min 1.90-1.915 on this batch i have
in this pic you see my load and lapua lead next to it if i pull depth back out to 1.976 thats 60 thnds longer i feel that bullet will not be deep enough? Or by chance am i way overseating this?
any help is greatly apprciated

View attachment 1281040
So I wouldn't change course mid stream, probably ideally I may have started with the lapua recipe from the start but its also just a guide.
That being said, Its not a big deal.
*Edit: .050" under isn't crazy just so long as you follow safe practices. As long as your "downloading" some and not going straight to max load. Generally people do want to load as long as possible to get max velocity and max case volume so you can get the most powder and most velocity potential for longest range in the end ultimately.

What's your recipe?
Is it a standard load out of a book? Are you starting at min load and working up like you should? I assume your current COAL is the one recommended by the book load your using? Or at least loading max MINUS 10% if either of the latter two I wouldn't worry there's quite a bit of safety margin built into loading and that's why you start with minus 10% etc.
What's your increments?
 
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OK.
Yup.
It looks like the "groove" will serve the same purpose as a "crimping groove" or "cannelure groove". There might be another (more industry specific) word for it. But at this point.... "I'm comfortable".

Note......
Some people might say that the grooved or the more pronounced cannelure style of bullet is "less accurate" than a smooth side bullet. Of course quality control has a lot to do with all that. Then, you'll note that a smooth sided bullet is usually found on Match Bullets. So probably.....there is something to that.

And, there is always the issue of possible deformation of the bullet when it's "crimped" into a brass case. Yeah.....one could go with a light or heavy. Or even, a barely there (say close to "slip") fit into the cartridge case.

Of course remember......
Recoil and feeding (from magazine or just placed into a chamber) will dictate much of what you're doing (trying for).

ME.....I don't want the bullet "telescoping" into the case or moving just a little (to change things up).

YES, Yes, yes.....there are many ways for different people to Get-R-Done.

ME....I stick with the two die sets. I use the 2nd die supplied (combo seater/crimper) with a moderate crimp for my semi auto ammo. Same for my ammo being put through my bolt action. LOL....KISS or just lazy. Whatever. It's usually "Good Enough" (for me).

But then......some people might insist......about using a third die - the FCD (Factory Crimp Die). They may just say that it's THE way to go (with a moderate to heavy crimp) with every cartridge produced. Especially, if/when loading for a semi auto or full auto firearm. They say that it adds to consistency. Like, trimming and annealing with every firing.

So then......
Which groove and/or what COAL (cartridge over all length) to use?

OK......that's where the "EXPERIMENTATION" comes in. And, keeping good notes.

As I said before......
The cannelure is (for me) a "suggestion". Though, normally a good one. Then, there is something to be said about just copying the COAL from a factory cartridge. Hummm......a cartridge that has the same or close enough bullet. Wink, wink....

So then......
Since I normally have only one die set per caliber. YEAH, fussing (even a little bit) with the settings or playing with different bullets, etc....etc...... is a slight problem with getting consistency. For me......I'm normally happy with choosing to get it set up "just right or close enough" to the last time. Assuming that the last batch that I made passed my expectations.

Remember, I'm lazy. Not to mention that I ain't shooting for a Gold Medal here.

Others will probably disagree. Whatever. That's OK too.

Aloha, Mark

PS.....As for....why three different grooves in one bullet?

I think (dangerous).......
That the manufacturer might have intended that the one bullet might/could/would be used in different cartridge applications?
 
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Also ultimately to me, your always better seating it deeper to begin with because like I said you can always seat them a little longer with no real disadvantages later on even if you have your final load and its near max you can still load groups of 5 longer .005” increments and try and find a "seating node" but like I said before. If you do this just make sure you don't jam one in the lands with a max load. Make sure you always have at least .020" bullet jump or so. (I'm not 100% sure on this but that's why I'm cautious maybe its fine to seat to the lands. I hear different things about it.)
But generally you can always seat longer out and pressure will decrease.

The one other factor I suspect may be at play is how far the base of the bullet is in the neck. You generally always want at least the diameter of the bullet in depth seated into the case neck. So .311 dia. You want the base at least .311 deep / 338 dia you want .338 deep and so on. Just a general rule of thumb.
 
ME.....I don't want the bullet "telescoping" into the case or moving just a little (to change things up).
Agreed this is paramount. Can result in kaboom. Proper neck tension with out a crimp should be .002" smaller than bullet dia. (-).003" max!
Any more than .003" thou and you will actually "work" the brass and loose all about 90% of your neck tension.
Otherwise you can just crimp it sufficiently.
 
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Understood, my new dilemma, @Pepe-lepew gave me a load data from Vihtavuori. saying COAL 1.976?
im between min 1.90-1.915 on this batch i have
in this pic you see my load and lapua lead next to it if i pull depth back out to 1.976 thats 60 thnds longer i feel that bullet will not be deep enough? Or by chance am i way overseating this?
any help is greatly apprciated

View attachment 1281040
You can see that the bullet base is BELOW the neck in that pic.
That bullet length seated below the neck adds nothing to the neck tension so seating it out 0.060" more will not diminish neck tension and may put the bullet base closer to the neck/shoulder transition.
For me, having the bullet base at the neck transition is ideal if it passes all the other OAL criteria.

I did zoom that pic and noticed a FOLDED-OVER Heavy Burr on the neck OD from trimming.
You need to remove that burr BEFORE loading.
jmo,
.
 

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