Questions regarding cartridge length on 8mm mauser: Spitzer vs Round nose

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deanyang

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So I am new to reload and bought some 8mm round nose bullets by mistake, all the data online shows overall length is with regards to spitzer not RN, I wonder if I can find data on round nose COL, or should I apply the same data as the spitzer rounds?



Also some questions regarding the trim length: on one site it tells me 2.230 and the other site told me 2.250, I measured my PPU casing, most of them are 2.24X, so I guess I should aim for less than 2.250?



Thanks for your help!
Dean
 
Gatehouse said:
What matters is the ogive position. Generally spitzer bullets will have a longer COAL than round nose
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Since there is no data on RN COL should I make spitzer according to manual and use it as a reference to estimate the RN length, with regards to ogive?
 
Do the bullets have a cannelure? What is the brand of bullets you are using? Am I hallucinating, your above post shows COL at 2.825 in for RN bullets. Regarding trim, if an empty sized case chambers OK, you are good to go. Hint - you should do this check for more than one reason.
 
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the loaded ammo needs to fit in your mag and in your chamber. past that the bullets should be seated at least one caliber deep in the case.

OAL isn't overly important, unless you are loading a really short OAL but even then you start low and work your way up.

the trimmed case lengths are the min and max. 2.230 is as short as you want it (a little shorter is fine) and you don't want it to be longer then 2.250, so your 2.240 is perfectly trimmed.

that data in first post shows round nose bullet over all length, also keep in mind as stated above, pointy bullets will almost always have a longer OAL, if you are loading to the lands.
they will be the same OAL if they are mag length limited.
 
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cosmic said:
Do the bullets have a cannelure? What is the brand of bullets you are using? Am I hallucinating, your above post shows COL at 2.825 in for RN bullets. Regarding trim, if an empty sized case chambers OK, you are good to go. Hint - you should do this check for more than one reason.
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yes as a matter of fact the RN has a cannelure! Should I just seat them till that cannelure is covered? Thanks!
 
Evanguy said:
the loaded ammo needs to fit in your mag and in your chamber. past that the bullets should be seated at least one caliber deer in the case.

OAL isn't overly important, unless you are loading a really short OAL but even then you start low and work your way up.

the trimmed case lengths are the min and max. 2.230 is as short as you want it (a little shorter is fine) and you don't want it to be longer then 2.250, so your 2.240 is perfectly trimmed.

that data in first post shows round nose bullet over all length, also keep in mind as stated above, pointy bullets will almost always have a longer OAL, if you are loading to the lands.
they will be the same OAL if they are mag length limited.
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Thank you for the detailed info!
 
OP, if you go to the 2015 SAAMI standard - is available for free download as .pdf file - page 54 - use the cartridge drawing, not the chamber drawing - shows that SAAMI sets cartridge brass length at 2.240"-.020" for 8mm Mauser. CIP in Europe may have different length for 8x57JS. Who knows who made your rifle or chamber reamer, or what length that they had in mind.

A chamber is reamed so that there is clearance for the case mouth - you do not want to hit that end - either when closing your bolt on a loaded round, or after that cartridge has been fired. Some of us do a cerrosafe chamber cast to measure, to be sure where that "end" is - some can figure out other ways to find it. Is very standard to trim to .010" less than maximum length - then measure each time you load - between firing and re-sizing, not unusual to see your cases grow in length until they need to be trimmed again. Even .025" short of maximum is not something to worry about - most feel that "all the same length" is at least as important as any specific length below maximum, but even .001" too long for your chamber is a bad thing.

As above, an overall loaded length is a pretty useless piece of information - the brass that you re-size needs to fit your chamber with minimum end play, not necessarily to someone else's chamber, then your loaded rounds need to first fit into your magazine with enough clearance that they will feed properly. Finally, some people have found more or less accuracy when their bullet ogive is closer or further from their barrel's leade. Your magazine length may or may not allow you to play with that. No one else can tell you a "best" length, because no one else has your rifle. I have a 9.3x57 Mauser barrel - the cast bullets that I will use will be about 1/8" out of the case mouth, before their ogive hits the leade - so simply not possible for me to consider how many thousandths off the leade do I want that bullet - as mentioned - very good rule of thumb is that the bullet gets seated at least one caliber deep into the neck - not counting boat tail. This assures a consistent "bullet pull" to allow the powder to properly build up pressure within the case.
 
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For trimming, the general guideline is 0.010" under the max published spec is a good target.

If you're shooting the 170gr Hornaday RN projectiles, I can say from personal experience that you can/should just seat the to cannelure, especially if you're crimping. There is no point in trying to "chase the lands" with those.
 
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I do not measure case length or worry about it too much. For every cartridge that I reload, I have that inexpensive Lee Case gauge set and several cutter and spinner sets. I resize a case - into the spinner on a drill - insert the Lee gauge - it might or might not peel anything, then a touch with a chamfering tool to break the inside sharp corner, then wipe with a water damp rag for my water soluble case lube - done - on to next case. I never did measure - do not care what number it is - Lee took care of that when they made that trim gauge - all my cases will be the same.
 
Potashminer said:
OP, if you go to the 2015 SAAMI standard - is available for free download as .pdf file - page 54 - use the cartridge drawing, not the chamber drawing - shows that SAAMI sets cartridge brass length at 2.240"-.020" for 8mm Mauser. CIP in Europe may have different length for 8x57JS. Who knows who made your rifle or chamber reamer, or what length that they had in mind.

A chamber is reamed so that there is clearance for the case mouth - you do not want to hit that end - either when closing your bolt on a loaded round, or after that cartridge has been fired. Some of us do a cerrosafe chamber case to measure, to be sure where that "end" is - some can figure out other ways to find it. Is very standard to trim to .010" less than maximum length - then measure each time you load - between firing and re-sizing, not unusual to see your cases grow in length until they need to be trimmed again. Even .025" short of maximum is not something to worry about - most feel that "all the same length" is at least as important as any specific length below maximum, but even .001" too long for your chamber is a bad thing.

As above, an overall loaded length is a pretty useless piece of information - the brass that you re-size needs to fit your chamber with minimum end play, not necessarily to someone else's chamber, then your loaded rounds need to first fit into your magazine with enough clearance that they will feed properly. Finally, some people have found more or less accuracy when their bullet ogive is closer or further from their barrel's leade. Your magazine length may or may not allow you to play with that. No one else can tell you a "best" length, because no one else has your rifle. I have a 9.3x57 Mauser barrel - the cast bullets that I will use will be about 1/8" out of the case mouth, before their ogive hits the leade - so simply not possible for me to consider how many thousandths off the leade do I want that bullet - as mentioned - very good rule of thumb is that the bullet gets seated at least one caliber deep into the neck - not counting boat tail. This assures a consistent "bullet pull" to allow the powder to properly build up pressure within the case.
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Thanks for the detailed advice, I think I will load an empty round to try out my chamber, I guess I will have to start with the bolt not be able to close properly and seating the bullet deeper bit by bit. I wonder if there is any other indication when the case mouth hit chamber end, other than the bolt hard to close?
 
Dude - You are having a hard enough time covering the basics! You chamber a resized and trimmed (or measured) case to ensure it fits in the chamber before loading it with powder and bullet. For trimming, get the Lee cutter and gage, they are cheap and easy to use. If your brass at 2.24X after sizing fits on a closed bolt you are fine, but you need to chamber or measure each of your used and resized brass. Otherwise, you may end up with loaded rounds that are improperly sized and wont chamber (bad news) or rounds that are out-of-trim that pinch the bullet at the neck (really bad news).
Dont bother chasing the lands yet, that can cause you more grief. Just load to the cannelure, thats what its there for. When you become reasonably proficient, you can start doing the tricks.
 
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For sure!! Is more important for you at the start to make many hundreds of rounds that go "bang" each time - that is, many reloading sessions. Load up 10 at a time if you want. Once you are comfortable with the process, then can start with the "tricks". And keep in mind, that the "tricks" worked in many thousands of dollars of bench rest rifle - usually - you may or may not see any benefit in your rifle. Is all about YOU loading for YOUR rifle - not somebody else's.
 
update: 2.24x works fine in both my mausers. My bullet is 150gr Speer hot cor. So if I seat a full caliber length it seems to be a bit too much. I ended up with 0.25 into the neck. Tried on both rifle. Chambers fine and magazine also took it

I will load 10 n test it out.
 
You should be more like .313 into the case for proper neck tension. I wouldnt be surprized if those work just fine. But if it was me id seat them .065 deeper.

Edit, well after a second look those bullets do lood pretty short though. A full caliber deep may be already into the taper or just close to it
 
Evanguy said:
You should be more like .313 into the case for proper neck tension. I wouldnt be surprized if those work just fine. But if it was me id seat them .065 deeper.

Edit, well after a second look those bullets do lood pretty short though. A full caliber deep may be already into the taper or just close to it
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Yup. Pretty short indeed. Now it look like this




I am thinking of backing out a bit
 
I wouldnt worry about the look of them as much as the function of them. If they feed and function well in the rifle, personally id leave them that short.

It doesnt look like the case is over hanging the taper at all.

Im sure either will be fine.
 
Evanguy said:
I wouldnt worry about the look of them as much as the function of them. If they feed and function well in the rifle, personally id leave them that short.

It doesnt look like the case is over hanging the taper at all.

Im sure either will be fine.
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thanks I will keep them short then!
 
Speaking of case lengths, I trim all my 8x57JS cases to 2.230"

I have a Husqvarna M1640 so chambered, and I cannot close the bolt
on a case longer than 2.242", so it is cut plenty short.

Dave.
 
Eagleye said:
Speaking of case lengths, I trim all my 8x57JS cases to 2.230"

I have a Husqvarna M1640 so chambered, and I cannot close the bolt
on a case longer than 2.242", so it is cut plenty short.

Dave.
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both my M48 and K98 can close the bolt no issue but I got my sharpie out and will take a second look at the case length

thanks!
 
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