Questions about Min. OAL & Max. OAL
- Thread starter Luger9
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IM_Lugger said:
Since when does a powder have a OAL?
Any spec for a min OAL is dependent on the actual bullet used. If you are not using the same bullet or one that is practically the same as the bullet specified then the OAL is meaningless.
For example if you have load data for a round nose bullet and you are loading a hollowpoint with a different bullet length then any OAL specified will not be correct.
Just as a sanity check I take into account the powder capacity in the case behind the bullet. (how far down into the case the bullet is seated) If you use a heavier bullet then for the same OAL the bullet would have to be seated deeper into the case and this would reduce the volume for the powder to burn. (There also are other issues to take into account when you have such a large difference in weight.)
For a small cartridge such as the 9mm Luger I like to seat as far out as possible (that still works in the gun) in order to minimise the possibility of an over pressure situation.
Wrong.Rudy H said:Since when does a powder have a OAL?
Any spec for a min OAL is dependent on the actual bullet used. If you are not using the same bullet or one that is practically the same as the bullet specified then the OAL is meaningless.
Powder has very much to do with bullet seating and OAL. Different powders burn at different speeds and therefore they generate different amounts of pressure. There is a general 'normal' OAL for different bullets be it 115, 124, 147 FN, RN, HP due to the profile and length, but they do vary with the powder being used.
With a 124Gr bullet (and this is straight out of my Lee Manual) HS-6 with a charge of 6.4Gr can be seated to 1.090 or more, TiteGroup with 4.1 Gr at 1.090 as well. Other powders that have a low OAL are ACCUR #5, Universal, wSUPER-FLD, HP38 and WIN 231 all around the 1.095 mark.
Powders such as the surplus powders or faster burning powders such as V-3N37, WIN-571, V-N320 and IMR 800X all list Min OAL at 1.130 or greater because they need more room to expand or you'll get a +P, +P+ load or a KB.
Seating 7.5 grains (max load) of Win 571 at a 1.090 (min is 1.135) would be a very bad idea.
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Please read my reply again. I never said a powder does not have an effect or should be considered. I questioned the following.
This statement does not take into account what bullet is used. You can't make a blanket statement like this without knowing the bullet. If you had two bullets both being conical, one being 124g and the other being 147g, you can't use a statement like the one quoted above. Then when you throw different bullet profiles in the mix then a general statement like that is even more off base.
Why do you think loading manuals specify the bullet used?
If you blindly follow the advice given without taking the bullet into account you end up with the following which is wrong.
This statement does not take into account what bullet is used. You can't make a blanket statement like this without knowing the bullet. If you had two bullets both being conical, one being 124g and the other being 147g, you can't use a statement like the one quoted above. Then when you throw different bullet profiles in the mix then a general statement like that is even more off base.
Why do you think loading manuals specify the bullet used?
If you blindly follow the advice given without taking the bullet into account you end up with the following which is wrong.
I agree with most of the above posts, but on a different note, somewhat off topic from the problem you are having:
From your pictures (thank you) I think you have too much crimp on your rounds. There is no reason to crimp so much that you 'deform' the jacket of a bullet in 9mm luger. If you pull them you really shouldn't see any sign that they were ever 'crimped'. Perhaps I'm seeing things. Save that rollover for your cannalured bullets. A snug fit is all you need. Reliability may become an issue as these headspace on the casemouth that looks somewhat 'rolled in'. Not necessary. If you can't push the bullet in with your thumb, that's enough. Back that die off a little. Have a good one...
From your pictures (thank you) I think you have too much crimp on your rounds. There is no reason to crimp so much that you 'deform' the jacket of a bullet in 9mm luger. If you pull them you really shouldn't see any sign that they were ever 'crimped'. Perhaps I'm seeing things. Save that rollover for your cannalured bullets. A snug fit is all you need. Reliability may become an issue as these headspace on the casemouth that looks somewhat 'rolled in'. Not necessary. If you can't push the bullet in with your thumb, that's enough. Back that die off a little. Have a good one...
Update
Wow....this thread got some activity since last night.
Ok, here's the update. I just got back from the range and test fired 20 rds (all A's) and everything worked out great. Not much of a difference in recoil from the 124gr FMJ rnd.
What I loaded was 121gr IFP, 4.7grs Green Dot and seated at 1.120 inches. I'm going to keep this recipe until I can get a hold of a Chrony. As long as it's within IPSC PF, I'm happy.
canuckgunny....you're correct about the crimp. The one in the picture is when I was playing around with my dies, trying to figure out what was a good crimp and there's a big friggin crease in that one where it's crimped. I have since back out the die to produce a light crimp.
Wow....this thread got some activity since last night.
Ok, here's the update. I just got back from the range and test fired 20 rds (all A's) and everything worked out great. Not much of a difference in recoil from the 124gr FMJ rnd.
What I loaded was 121gr IFP, 4.7grs Green Dot and seated at 1.120 inches. I'm going to keep this recipe until I can get a hold of a Chrony. As long as it's within IPSC PF, I'm happy.
canuckgunny....you're correct about the crimp. The one in the picture is when I was playing around with my dies, trying to figure out what was a good crimp and there's a big friggin crease in that one where it's crimped. I have since back out the die to produce a light crimp.
agreed
Yes and no; you still get an idea... I think it’s save to say that Tite group and HS6 will have shorter OAL (with nay bullet) than powders like Herco, Blue dot or Green dot.
Luger9 if I were you, I’d switch to another powder (or use FMJ bullet); since you have no way of knowing the pressure of your load; IMO 1.20 is too short. OAL of 124gr FMJ is 1.50", now because of the cavity a HP bullet is usually longer than FMJ, which means OAL of a HP load would have to be even longer than of FMJ load... Plus Green dot is not the best powder choice for 9mm...
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IM_Lugger said:
I will be switching powders, I'm waiting on some Titegroup. The one thing I really don't like about the Green Dot is the inconsistency of the powder measure...I believe the granules are too big and they get stuck. My dad will inherit the bottle of Green Dot for his shotshells.
For now I'll be using the bullets that I have, but later on may be switching to 147gr FMJ. I've always liked the heavier bullet anyways, I was trying this new stuff out because...well....it's new and other than the OAL dilema it's a nice bullet that flies very well through my barrel.
Powders don't have a min OAL, but different powders combined with the same weight and type of bullet will.
From Modern Reloading, 45ACP, 230 grn jacketed bullet:
Accur#7: 11grns, 942 fps, 20k psi, 1.250 oal
Unique: 6 grns, 895 fps, 16k psi, 1.190 min oal
Solo 1000: 5.5 grns, 848 fps, 19k psi, 1.250 oal
From Modern Reloading, 45ACP, 230 grn jacketed bullet:
Accur#7: 11grns, 942 fps, 20k psi, 1.250 oal
Unique: 6 grns, 895 fps, 16k psi, 1.190 min oal
Solo 1000: 5.5 grns, 848 fps, 19k psi, 1.250 oal
OAL is also handgun-dependant
Just to add to the «simplicity» of the discussion , OAL depends also of which handgun you shoot your bullet with.
In fact, what matters is not truly OAL, but distance from case mouth (where the 9mm case headspaces in the chamber) to ogive (point of contact of the bullet with the rifling). This is independant of bullet shape (hollow point, flat point or round nose).
There are variations from a handgun make to another in the actual distance between the headspace point in the chamber and the start of the rifling (also called landings). For instance, a CZ75 has about 0,050" while a Sig P226 X-Five has almost 0,150". This means that you can reload 9mm's at 1,160" very well (and very accurate load) with the Sig, but this will never work within the CZ (because of its much shorter landings distance). The bullet will hit the rifling way before the case could headspace properly (in fact, not letting this ammo to chamber).
There is one simple way of measuring this thing with your reloads (once you know what it should be for your handgun). Just take your round and insert the bullet end into barrel muzzle. The «ogive» point will hit the rifling. Now measure with your caliper the distance between the muzzle and the case mouth. It should measure around 0,050" for the CZ. This ends up with ammos with an OAL around 1,100" (with the flat point bullet).
Now, obviously, you should be careful with the powder charge used, particularly if your OAL is shorter than the one given in the specs of your load. All these things are inter-dependant !
Well, this is my own experience and understanding so far
Hope it helps ...
Warther
Just to add to the «simplicity» of the discussion
, OAL depends also of which handgun you shoot your bullet with.In fact, what matters is not truly OAL, but distance from case mouth (where the 9mm case headspaces in the chamber) to ogive (point of contact of the bullet with the rifling). This is independant of bullet shape (hollow point, flat point or round nose).
There are variations from a handgun make to another in the actual distance between the headspace point in the chamber and the start of the rifling (also called landings). For instance, a CZ75 has about 0,050" while a Sig P226 X-Five has almost 0,150". This means that you can reload 9mm's at 1,160" very well (and very accurate load) with the Sig, but this will never work within the CZ (because of its much shorter landings distance). The bullet will hit the rifling way before the case could headspace properly (in fact, not letting this ammo to chamber).
There is one simple way of measuring this thing with your reloads (once you know what it should be for your handgun). Just take your round and insert the bullet end into barrel muzzle. The «ogive» point will hit the rifling. Now measure with your caliper the distance between the muzzle and the case mouth. It should measure around 0,050" for the CZ. This ends up with ammos with an OAL around 1,100" (with the flat point bullet).
Now, obviously, you should be careful with the powder charge used, particularly if your OAL is shorter than the one given in the specs of your load. All these things are inter-dependant !
Well, this is my own experience and understanding so far
Hope it helps ...
Warther
