OAL for SWC vs. cone vs. RN for 9mm


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cubhead
September 25, 2011, 10:42 AM
New to realoding. Working on my first batch of 9mm cast RN & SWC.
After looking thru several reloading books, I dont see much data on the the different types of cast bullets. Most just list them as "cast" or "lead".
My question - for say a 125 gr cast bullet, is there any difference in the OAL for the RN or SWC or cone bullet for the same powder charge?

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rfwobbly
September 25, 2011, 11:28 AM
There will be a difference, but by beginning at the "starting load" and working up, all the minor differences get ironed out.

cfullgraf
September 25, 2011, 11:37 AM
I have found with auto loading pistols, the different shape bullets frequently have different cartridge overall lengths to make for reliable operation of the pistol.

As rfwobbly said, work up your loads as you are finding the optimum bullet position.

wharvey
September 25, 2011, 11:47 AM
There is nothing really magical a out OAL. Start with the suggested OAL and starting load. Load in small batches while doing load development. Adjust the OAL for functioning reliability, and possibly accuracy. Then start adjusting the charge.

Some autoloaders are picky about length and remember bullet depth does affect pressure so be very careful when you get into the upper half of the charge weight.

BTW, you may or may not need to be above starting load to get autos to function.

cubhead
September 25, 2011, 12:30 PM
Great info - thanks!

rcmodel
September 25, 2011, 01:41 PM
I dont see much data on the the different types of cast bullets.You need to buy either a Lyman #49 reloading manual.

http://www.lymanproducts.com/lyman/publications/49th-edition.php

Or a Lyman Cast Bullet Handbook.
http://www.lymanproducts.com/lyman/publications/cast-bullet.php

Or both.

They are invaluable for anyone even considering reloading & shooting cast bullets.

I don't know of any other reloading manual with much if any cast bullet data, because none of the big bullet & powder companies that publish manuals make or sell cast bullets.

What little lead bullet data that is published is probably for Speer & Hornady swaged soft lead bullets.
Data for them is not the same as for cast bullets.

As for OAL of the different bullet shapes?
Yes, they are going to be different.
For instance, a 125 RN bullet will be longer then a 125 SWC or TC bullet shape.
The reason being is that the RN comes out of the case getting smaller then the bearing surface of the bullet.
The SWC and TC bullet is full dia to the front of the front driving band.
That makes the OAL of the loaded round longer for the RN then for the SWC or TC.

rc

bds
September 25, 2011, 01:46 PM
I keep seeing people using OAL specified in the published load data or using trial and error for different pistols. This is not the best reloading practice and determining OAL should not be a guessing game. Most published load data are made using test barrel fixtures and not actual pistols. For each new bullet we use for reloading, we need to determine the OAL that will work in our individual pistols/barrels before conducting the powder work up.

While most pistols will feed 9mm RN bullets at varying OAL (say typically around 1.125"-1.135"), depending on the bullet nose profile (ogive), as rc posted, you may need to use shorter/longer OAL for your pistol. With any new bullet, you should always determine the MAX OAL using your barrel and IDEAL OAL by manual feeding from the magazine to ensure reliable feeding/chambering before conducting powder charge work up.

1. MAX OAL determines the longest OAL that will drop freely in your chamber without hitting the rifling. Using your barrel out of the pistol, drop a sized case into the chamber to ensure you are full-length sizing your case (it should fall in freely). Next, make a dummy round (no powder/primer) starting at SAAMI max length and taper crimp .020" wider than the diameter of the bullet (.375" for .355" bullet and .376" for .356" bullet). Drop the dummy round in the chamber and incrementally decrease the OAL until the round fall in freely and spin without hitting the rifling.

2. IDEAL OAL determines the longest OAL that will feed and chamber reliably in your pistol/barrel/magazine. Starting at the MAX OAL, manually feed your dummy round by releasing the slide (do not ride the slide with your hand). Incrementally decrease the OAL until the dummy round feed/chamber reliably.

3. POWDER WORK UP. Once you determined the MAX and IDEAL OAL, then conduct your powder work up from start charge to identify the charge that will reliable cycle the slide and produce consistent accurate shot groups.

cubhead
September 25, 2011, 01:50 PM
I have Lymans 49th reloading hand book but they don't even list 115 or 125 grain cast bullets. Does their cast bullet book contain more data or is it just abridged?

cubhead
September 25, 2011, 01:52 PM
bds - that's excatly what I was looking for. Thanks!

Quoheleth
September 25, 2011, 10:11 PM
My Lyman Pistol & Revolver book shows data for three different 120-125gr profiles, a round nose, a flat nose, and a conical nose. All three have different OALs and, therefore, slightly different charges of powder.

Even though I run 125gr with a couple different profiles, I feel comfortable using the 120gr data, especially the info on the short OAL cartridge data that my CZ requires (sub-1.068").

Q

ranger335v
September 25, 2011, 10:23 PM
"..is there any difference in the OAL for the RN or SWC or cone bullet for the same powder charge?"

Not specifically but you understand that now.

Fact is, virtually all cast bullets will have a crimp groove. Seat a test/dummy round so you can crimp in that groove and try it for feeding and chambering. If it works smoothly that's all you need for an OAL.

rcmodel
September 25, 2011, 10:23 PM
I have Lymans 49th reloading hand book but they don't even list 115 or 125 grain cast bullets.Lyman lists cast bullet weights "as cast", meaning no sizing, & bullet lube has been added yet.
That can account for the missing 5 grains.

They also list the 9mm bullet weights "as cast" from #2 alloy.

Using a harder alloy like Linotype will make them lighter.
Using a softer alloy like pure lead will make them heavier.

What you want to look at is the bullet shape, bore riding, or full dia length, and number of driving bands when comparing your 125 to their 120 bullet weight.

For that matter a 120 bullet could be used with 1115 data, or visa versa, as long as the bullet shape & bore dia driving bands are about the same.

+/- 5.0 grains is meaningless when it comes to cast lead bullets.
It's the full dia bore riding length of the bullet design (bore friction) that changes pressure radically.

rc

cubhead
September 26, 2011, 09:05 AM
I followed BDS's suggestion (find MAX OAL, then IDEAL OAL) and what I learned was the following:
I am using Missouri bullets, 9mm cast, 115 grain RN, 125 grain SWC & 125 grain TCRN (cone)

115 gr CRN OAL = 1.120"
125 gr SWC OAL = 1.127"
125 gr TCRN OAL = 1.086"

My next step is to start with min loads for each, using Bullseye powder.

Thanks for everyones help! This is a great site!

Quoheleth
September 26, 2011, 09:21 AM
FWIW, I've talked with Brad quite a bit about the 125 Cone and SWC profiles. For some reason, medium-speed powders seem to work better than really fast stuff like Bullseye. If you start to experience keyholing with Bullseye try a slower powder. There was a thread here on THR earlier this summer with the OP having perfectly side-profiled holes in his targets. It was diagnosed as too fast of powder.

Brad's getting reports of HS6 being very good. My CZ85 loves the 125gr LRN with AA#5 and Universal, so I loaded up a couple batches with mid-range loads of both powders. I hope to get out today to run those and see how they work.

Q

john16443
September 26, 2011, 11:50 AM
Maybe the earlier post regarding keyholing was me, see post #9 and onward in this thread http://www.thehighroad.org/showthread.php?t=600000 pics of the targets included. I was finally able to stop the keyholing with a load of W231, but never bought more of the 9cone bullets. I had similar experiences with other cast lead bullets and am working with Matt at Dardas on a solution that may involve different flaring and deating dies along with properly sized bullets. I haven't tried any lead RN bullets in the SR9 yet, nor have I tried any of the SWC style 9mm bullets available from MBC and Penn.

FWIW, FMJ, plated, and moly coated bullets (Precision, Black Bullet Intl) work without problems.

If you enjoyed reading about "OAL for SWC vs. cone vs. RN for 9mm" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!