Affect of OAL on pressure


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Okiecruffler
October 1, 2003, 10:18 AM
I know that shortening OAL will increase pressures, sometimes well beyond safe. But I'm about to load some .357mag for my Contender and I want to set the bullet out as far as possible to eliminate jump to the rifling. Right now I'm looking at an OAL of 1.69''.

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Poodleshooter
October 1, 2003, 11:12 AM
Caution: running a bullet directly into the lands (which might be possible on your T/C) can also cause pressure increases,even though there is more volume under the bullet. This is the exception of course
As a general rule, seating to a longer OAL with a given bullet decreases bullet pull, decreases pressure, decreases bullet jump and might increase accuracy.
One problem with messing with really long OAL's in a .357...if you're using WW296,H110 or a similar powder you need to know that bullet pull (resistance to the initial stages of the burn) is critical. If that bullet is seated out too far, not crimped enough, and/or the load is just a little too light, you'll get a squib or see very low pressures and velocity. Those powders need a lot of resistance (bullet pull) to ignite fully.

Black Snowman
October 1, 2003, 11:15 AM
One would first assume that this would reduce pressure, but if it's actually resting against the rifling lands it can create early resistance and make a large spike. Ideally for consistancy and safety my BEST GUESS (I haven't actually done this) would be to have the seating depth set so it has moved enough to straighten the crimp before contacting the lands so that you're not adding the resistance of the crimp to the resistance of the lands.

Somone with more experiance should step in now and set me straight :)

edit: AH, poodleshooter beat me too it! And even mentioned the powder issues which I was going to point out with H110, didn't know about the other as I'm not a big Winchester powder person. Something to file away in my powder data spreadsheet.

Okiecruffler
October 1, 2003, 11:23 AM
I've purposely avoided using H110 because I've heard it's real cranky in many situations, but alot of the loads suggested to me use it, so I might have to belly up. With the OAL I have now, I'm just backed off the rifling, and have a good tight crimp. Just kinda trying some different ideas.

Black Snowman
October 1, 2003, 01:44 PM
H110 is a lot more forgiving in bigger cartridges. In .357 you pretty much have to go full-tilt. .44 there's some margin for error and in my .50 AE I can make loads with it that will barely lock back the slide on my Desert Eagle. Those are 5 grains down from max (27gr as opposed to 32gr).

What kind of accuracy are you getting now? Do you really feel the ammo is the limiting factor?

Okiecruffler
October 1, 2003, 02:02 PM
With factory S&B I'm getting 0.64'' groups at 50yrds and 1.52'' at 100yrds. My best reload so far was 170gr Seirra with 8.7gr of BlueDot. Best it could do was 0.98 inches at 50yrds. I should be able to at least equal that S&B load.

Poodleshooter
October 2, 2003, 01:01 PM
Two things that might help:
1. A profile crimp die (such as Lee's FCD) to make crimp more uniform and less dependent on trim length
2. Really carefull hand measuring and weighing of powder. I have a hard time getting accurate throws using ball powders in my handguns. Still, too my mind, used to shooting .357 with iron sights at 25yds, that isn't bad!

Okiecruffler
October 3, 2003, 09:18 AM
I'm going back to weighing each charge, and I think that will probably do more for accuracy than increasing length. My thrower is a Lee measure, and while I like most of the Lee stuff, I've never fully trusted this piece.

Steve Smith
October 3, 2003, 09:28 AM
Okie, I've found H110 to be very easy to use as long as you only use it in powerful loads. If you want a plinking load use something else, but if you want to hurt something, a lot, use H110 and you can feel safe about doing so.

Okiecruffler
October 3, 2003, 10:12 AM
I was going to pick up some H110, but the two shops I like to buy from didn't have any, I guess I can go mail order, but I hate to pay shipping.

Steve Smith
October 3, 2003, 10:19 AM
Look for W296. It's the same stuff.

Werewolf
October 3, 2003, 12:45 PM
I was going to pick up some H110, but the two shops I like to buy from didn't have any, I guess I can go mail order, but I hate to pay shipping.


__________________
John A. Monroe 10-32


Small world - I live about a block away from Del City...

Where do you buy powder? Last time I was in SW Shooter's Supply they had H-110 but that was about a week ago.

Been by the Gun World (old Mashburn Arms - moved) shop on Sunnylane yet? The owner says they're gonna carry a wide variety of powder - I'll believe it when I see it - trouble with them though is they're way, way over priced (on everything - and with one exception they're all pretty much a'holes too).

Poodleshooter
October 3, 2003, 01:52 PM
Another full power .357 option if you're powder shopping is Hodgdon's Li'l Gun. It's slightly slower than H110, and yields the same velocities with less pressure. I've not used it, but I'm sure others here have.

Okiecruffler
October 3, 2003, 03:32 PM
That may be why I can't find it. It took me forever to find Herc2400, didn't realize that alliant had bought them out. Shows how long it had been since I bought any.

Werewolf,
There are several of us Okies on the board, I keep thinking we should all get together, but who has the time. I usualy get my stuff at OutdoorAmerica, but lately I've been going out to Mustang gun and pawn. Last time I was in SW Shooters it looked a garage sale in there, but maybe its gotten better. And since the new range is just Mashburn Arms I won't set foot in there. I don't mind a good gouging once in a while, but I prefer not to be insulted at the same time.

Werewolf
October 3, 2003, 06:57 PM
And since the new range is just Mashburn Arms I won't set foot in there. I don't mind a good gouging once in a while, but I prefer not to be insulted at the same time.

__________________
John A. Monroe 10-32

Hehe...
And I thought it was just me who considered them overpriced and - uhhhh - less than polite. And they lie too. I asked them what they'd sell me Magtech .45LC for once (before I started reloading) and told 'em I could get it at OAS for $15.36 a box. The young guy made a big deal out of no way could they sell it at that then said he'd sell it to me for $18/box. I figured what the hell - it'd save me the drive across town so I told him next time I was in his store if he had any I'd buy it from him. When it came in the price had been jacked up to $22/box. I just laughed. Last time I was there (the trailer) the two boxes he "ordered just for me" were still sittin' on the shelves.

I'm gonna try out their range though. Supposedly it's the same kind that LE's use and is unique to Oklahoma. 99 Different computer controlled target programs for moving targets in different directions, etc. At $10/hour that's pretty steep (considering I can shoot on my daughter's land for free) but if the range is as good as they say I may just plop down $200 for a year's membership ($1 per visit with membership). He'll lose money on me with that deal - but what the hey - not my problem.

SW Shooter supply isn't that *gentile* of a store but they have the best selection of reloading supplies in OKC and the folks there actually seem to appreciate your business. OAS is a good store too but the employees are either ignorant or arrogant (sometimes both) and both types are just annoying. Unfortunately they have the best selection of handguns and prices on the shelf in OKC that I've found.

If you shoot IPSC or CAS we may have run into each other and not known it.

Have a good one.

MrPhil
October 3, 2003, 07:57 PM
Speer #11 shows OAL 1.690" 357mag loads for Contenders. The bullets are Speer TMJ's, 180 and 200 grains. Powders listed are: 680, H110, 296, IMR4227, AA#9, and 2400. They are listed as "silhouette" loads.

Okiecruffler
October 4, 2003, 10:14 AM
If you want to meet some nice guys and see a really impressive selection of used stuff (just try to find a 17 rem at outdoor america, let alone 3) take a drive out to Mustang gun and pawn. I've got a Mitchell pistol in their back room now trying to make its way home. I don't shoot IPSC or CAS, but I'd like to do the CAS thing, and if they ever do WWII reenactments, I'll be so soviet my eyes will be red.

Jeeez, I'm hijacking my own thread...

HSMITH
October 4, 2003, 12:38 PM
Okie, quit weighing charges and get a good powder measure. Weighing charges with a powder that meters decently is a waste of time and is counter-productive to accuracy. Find a serious benchrester that weighs charges and you have found something no one else has.

WESHOOT2
October 5, 2003, 07:01 AM
Ditto volume vs weight.

Okiecruffler
October 5, 2003, 12:42 PM
Speaking of volume measures, what do you guys think of those Lee powder scoops? I have a set around here somewhere that I've never used.

HSMITH
October 5, 2003, 01:08 PM
The dippers work VERY well but you must use them EXACTLY the same way every single time or you will get variations much like the measure you are using now. Get a good measure like an RCBS or a Redding and hard mount it to a dead steady bench. Set the measure for the desired weight, then drop 10 or 15 charges in a bowl and put them back in the measure. Then start dropping your charges to load with. Operate the handle exactly the same each time, and hit the stop in both directions. Check a few charges as you load, as long as there are not gross variations just keep plugging.

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