Cartridge Overall Length differences.

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12 years 5 months ago #12193 by BUILDING MY SASS
Replied by BUILDING MY SASS on topic Re: Cartridge Overall Length differences.
Red Scout it correct...I forgot to add a few things...Learning to "Reload" is the easy part...Working for Precise Loads for Maximum Accuracy is a "WHOLE OTHER GAME"...My loads do well at 1 to 300 yards...No Pin Point...but they would do the job...Each AR-10 is different...what works in mine...might not work in yours...I know it sounds weird...but True none the less...In the Reloading category there are some threads that have some very good places to start...as far as bullets, powder, brass, primers, and so on...Each has their own favorites...if you are just looking to take a "Hog Head"... :evil: :whistle:
Then the basic loads mentioned will do the job...Remember the Most Important Part...DO NOT USE MAX LOADS...it can and will damage your rifle...
BMS
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12 years 5 months ago #12195 by Moby
Replied by Moby on topic Re: Cartridge Overall Length differences.
Understood.
I purchased a log book to record loads, bullets, etc and results.
I cannot get the .308 case horder from Hornady until 9/18 (backorder)
As I mentioned I need enough range/reloading time to nail a 5" group at 400 yards. (4" if I can get there) Once I get that down I'll work on reaching out farther.

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12 years 5 months ago - 12 years 5 months ago #12204 by BUILDING MY SASS
Replied by BUILDING MY SASS on topic Re: Cartridge Overall Length differences.
Perfect example of what I mean....IMR 4895
43.6 gr...Rocks at 100 yards...200 not to bad...300 all over the place...
42.5...sucks at 100 yards....Rocks at 300...
Using 150 gr Hornady FMJ....
I just haven't had the time to pin point the "Sweet Spot" between them....so I have different boxes...LOL... :S
I don't shoot to many reloads...I Prefer to Feed my Baby Factory Food.... :whistle:
168 gr Hornady A-Max...but the cost is going through the roof... :pinch: ;)
Especially if she is Hungry and my Finger is Itching.... :dry:
BMS
Last edit: 12 years 5 months ago by BUILDING MY SASS.

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12 years 2 months ago - 12 years 2 months ago #12949 by zfk55
Replied by zfk55 on topic Cartridge Overall Length differences.
COL. A misleading term. A true cartride OAL can only be based on projectiles that are absolutely identical in all respects, IE: A FMJ, not hollowpointed.
The correct seat depth for your rifle depends (begins) specifically on the point at which the ogive contacts the lands/grooves of your barrel. That has little if anything to do with the base to tip measurement of your loaded cartridge.

This is an excerpt from my Dad's discussion of reloading for beginners.

To determine proper seat depth for any given projectile, keep in mind that the measurement is only valid when the contact of the bullet's ogive and the lands/grooves is determined.
Your manual says OAL is 3.020?... maybe for that bullet that they used, but only for that bullet profile, not all others. Projectile profiles vary from mfg to mfg.and application to application. So how do you do it?

There are any number of ways, but I've always used the same methodology. Take a sized, empty and unprimed, uncharged case, start a bullet into the case mouth leaving it protruding further than is apparently correct. Place it in the rifle's chamber by hand, ease the bolt into full battery and "smartly" eject it. Measure that OAL and seat it 2 to 4 thousandths deeper. This is a good start. Later, when you've become more deeply involved in data gathering, you may want to play with seat depths to find the sweet spot for your cartridge. I have specifics I use regularly.
Yes, there are other ways. If you like your way better .......use it.
Once you determine your chambered OAL for that bullet, screw your seating die down until the mouth of an empty case stops the descent and back it out a full turn. Lock the die in place and back out the seater. Note that a good seating die will index on the ogive, not on the tip of the bullet.

That method is only going to work for one bullet profile, and it its a hollow point its not going to be accurate anway since few meplats are the same even in the same box. Your bullet seater should be indexed behind the tip ahead of the ogive, not on the tip of the bullet. A Sierra 175 MK is not going to be the same as a Berger 175 VLD at all. Both should index on an area ahead of the ogive, but not all ogives are the same distance from either the case mouth or the bullet tip. If you use just the tip you're going to have two completely different freebores for the same caliber, weight and charge with likely two different results.

Now measure it and decide how far off the lands you want to begin. Note that figure and begin working out your load, adjusting seat depth as you go. But remember that was only for that bullet profile. Change profiles and you're back to square one.
P. St.Marie


Latigo
Last edit: 12 years 2 months ago by zfk55.
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12 years 2 months ago #12951 by BUILDING MY SASS
Replied by BUILDING MY SASS on topic Cartridge Overall Length differences.
:I-agree:
I need to come spend a week or two with you and your dad... :bow:
I know I would learn alot more than I think I know.... :whistle:
I use factory rounds of the same load type and my Manual to determine what length every thing needs to be...so far...No problems other than stated...time to find the Sweet Spot....I am looking forward to using the R-15 at 42.5 as your father suggested a long time ago for the Wilson...or was that you... :pinch: ...dang old age...CRS....anymore... :banghead: :laugh: :cheers:
BMS

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12 years 2 months ago #12952 by 13fcolt
Replied by 13fcolt on topic Cartridge Overall Length differences.

BUILDING MY SASS wrote: :I-agree:
I need to come spend a week or two with you and your dad... :bow:


Roger that. I learn something just damn near every time he posts.


Whats the right way to say ogive ? I hear it oh-jive and oh-give interchangeably, sometimes in the same conversation.

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12 years 2 months ago - 12 years 2 months ago #12954 by Moby
Replied by Moby on topic Cartridge Overall Length differences.
Sir thank you for the wealth of information. I am new to the long range sport of shooting and the AR 10 .308 platform. You've just given me a tremendous amount of information to research and process. I've 180 rounds through my Ar and have not yet reloaded a single cartridge. I have everything to do so, except proper knowhow. My thought is the proper slow learning curve will put me closer to small groups at long range faster.

You certainly have a wealth in info.


zfk55 wrote: COL. A misleading term. A true cartride OAL can only be based on projectiles that are absolutely identical in all respects, IE: A FMJ, not hollowpointed.
The correct seat depth for your rifle depends (begins) specifically on the point at which the ogive contacts the lands/grooves of your barrel. That has little if anything to do with the base to tip measurement of your loaded cartridge.

This is an excerpt from my Dad's discussion of reloading for beginners.


To determine proper seat depth for any given projectile, keep in mind that the measurement is only valid when the contact of the bullet's ogive and the lands/grooves is determined.
Your manual says OAL is 3.020?... maybe for that bullet that they used, but only for that bullet profile, not all others. Projectile profiles vary from mfg to mfg.and application to application. So how do you do it?

There are any number of ways, but I've always used the same methodology. Take a sized, empty and unprimed, uncharged case, start a bullet into the case mouth leaving it protruding further than is apparently correct. Place it in the rifle's chamber by hand, ease the bolt into full battery and "smartly" eject it. Measure that OAL and seat it 2 to 4 thousandths deeper. This is a good start. Later, when you've become more deeply involved in data gathering, you may want to play with seat depths to find the sweet spot for your cartridge. I have specifics I use regularly.
Yes, there are other ways. If you like your way better .......use it.
Once you determine your chambered OAL for that bullet, screw your seating die down until the mouth of an empty case stops the descent and back it out a full turn. Lock the die in place and back out the seater. Note that a good seating die will index on the ogive, not on the tip of the bullet.

That method is only going to work for one bullet profile, and it its a hollow point its not going to be accurate anway since few meplats are the same even in the same box. Your bullet seater should be indexed behind the tip ahead of the ogive, not on the tip of the bullet. A Sierra 175 MK is not going to be the same as a Berger 175 VLD at all. Both should index on an area ahead of the ogive, but not all ogives are the same distance from either the case mouth or the bullet tip. If you use just the tip you're going to have two completely different freebores for the same caliber, weight and charge with likely two different results.

Now measure it and decide how far off the lands you want to begin. Note that figure and begin working out your load, adjusting seat depth as you go. But remember that was only for that bullet profile. Change profiles and you're back to square one.
P. St.Marie


Latigo

Last edit: 12 years 2 months ago by Moby.

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