What's a good 9mm load to start with?

[rfwobbly]

As for oal, I don't know yet, but extremely close to the same length as a factory 147jhp and a similar profile.

Bro Possom -
You cannot guess about the length. The seating depth directly determines the volume inside the cartridge case. The volume inside the case directly effects the chamber pressure. The chamber pressure determines whether you get to keep your hand and eyes.

This is not play time. Close is not good enough. You have to be at or longer than the OAL given in the data book for that weight bullet. You have to be able to know and hold the OAL within a very tight tolerance.

 

[zxcvbob]

Green Dot works very well with cast bullets in 9mm.

Alliant has load data in their old databook (page 16): http://www.thehighroad.us/attachment.php?attachmentid=81593&d=1216513445

I would use 5.0 grains of Green Dot. BTW, consistant bullet seating is *very* important for loading 9mm ammo that shoots accurately. Find the length that works the best with your bullet and your guns, and stick with it.

 

[coyotehitman]

All I have ever used is 3.9 gr of 231 and 125 grain RN bullets. It has functioned everything from Glocks to CZ's without problems.

 

[possom813]

Right on, so I probably shouldn't see if these go bang tomorrow then.

I need to dig up a set of calipers

This also wasn't something that I read in the manual, I haven't read anything about OAL yet, just saw it mentioned a couple of times. I was under the impression that the bullets go where the bullets go and that was it.

No reload shooting tomorrow it doesn't look like, so I'll stick these on the shelf as the "1st Reloads" and keep them as a memento of the time I didn't shoot my eye out.

 

[rfwobbly]

Metrology 101

Possom -

You can get a really nice digital 6" caliper at places like Northern Tool or Harbor Freight on Sundays. You may have some of these stores locally, or they both have websites. Calipers usually cost about $25-$35. Look for one that reads in MM and Inches, with a resettable zero, and a carrying case.


Understanding Tolerances
The accuracy needed is inferred. All measurements have a tolerance. When a number like "1/16" is stated, it usually infers a fractional tolerance of the smallest unit on the ruler you are using, say 1/64. So it is really saying "1/16 ±1/64". Follow?

So a number like 1.02" infers a plus/minus tolerance also measured to 2 decimal places, such as 0.01". So it follows that a number like 1.160" infers a tolerance also measured to 3 decimal places, such as 0.005".

The smallest measurement the human eye can detect is generally considered to be 1/64" (~.016"). This is 3 times larger than our 0.005 from above. So when you are given a 3 decimal place OAL, the instructions infer that you MUST get an instrument capable of measuring to 3 decimal places, such as a micrometer or a caliper.

Back in the 50's, reloading used to be the province of machinists and technicians accustomed to working to fine tolerances. All this was innately understood by them at the reading. Now that reloading has moved more into the realm of the hobbyist, this has not been very well explained.

In your particular case, fine tolerances are a must due to the fact that the 9mm Luger case has such a small internal volume. Much smaller than almost any other common round. As I said before, due to the very small case, small changes in OAL make for big changes in chamber pressure. So the 9mm is much more highly sensitive to changes in OAL, and extra special care needs to be exercised.


Other Uses
Calipers can also be handy in detecting over pressure, since one of the signs is case growth at the base. Calipers can also be handy is insuring there is not too much taper crimp, a contributor to higher chamber pressure. So a caliper is a very handy instrument to have. You will never regret the purchase.

Hope this helps!

 

[Walkalong]

You can get a really nice digital 6" caliper at places like Northern Tool or Harbor Freight on Sundays.

Harbor Freight Calipers They go on sale pretty often and work great.

 

[rfwobbly]

Walking -

You're correct. I'm using a set of Harbor Freight 6" stainless steel digitals picked up there on sale in early December for $12 !! However, I didn't want to mention that, not knowing if the sale was still going.


It's simply amazing what the Chinese have been able to accomplish with all our money and technology.

 

[possom813]

These any good, or any opinions on them???

http://www.manventureoutpost.com/outdoor/index.php?main_page=product_info&products_id=12695

 

[rfwobbly]

Those SEEM to be the same as ones I have, but there is no mention of the metric-inch readings which is really nice. I got the photo downloaded and blew it up in PhotoShop, all to no avail. Still couldn't read the script.

I think there must be one place in China making one set of calipers which is re-labeled 10,000 ways. You might want to order over the phone and ask the guy in India if it has that capability.

So I feel 94.35% certain it's a good set.

 

[zxcvbob]

Those look about the same as the HF ones. I have a pair of HF calipers, and they work great, but the original battery didn't last very long and neither did the spare. I put a name-brand battery in and it has lasted a couple of years.

BTW, if you have some factory ammo there, you can use one as a gauge to set your seating die. You won't know the actual length, so you use the minimum load data (about 4.5 grains of Green Dot with your 125 grain bullets) and it should be OK. Don't load a whole case of them, just in case it's too weak to cycle your gun. But I've used 4.5 grains of Green Dot with a little heavier bullet and it was a good "+P" load.