How to determine best COL (9mm)?

[prof_fate]

I'm new to reloading and ran a batch of LRN and wasn't impressed with the accuracy. Not sure what to blame or work on first (tried 3 different loads of the same powder - all were about the same). Same COL.

From what I've read COL is a big determinate in how accurate the ammo/gun is.

Recipes list a min COL and there is a max for the caliber of course.

So how do you determine the best COL? If you change bullets (weight or shape or material) or powder (type or charge) do you have to start over from scratch, or would the COL for your remain the same?

[cranky cj]

I don't know about all the rest of the stuff but this is what i do; look up the book's max COL listed and set the first one to that and see how well it chambers, if it won't chamber I keep shortening, or pressing it in, until the round will chamber without any hangups. So, i end up with the max COL for my particular gun. the last 9mm and 45acp reloads were, I thought, accurate. I've measured factory ammo and it usually comes in way under my layman COL listed length. Lets see what everybody else has to say.

[JLA]

In a rifle yes, seating depth and how the case is sized makes a difference. With handgun ammo the powder used is the biggest accuracy factor. If you arent getting an accurate load with any charge weight within the recipe for that powder then switch powders. Ill tell you now that one of the absolute best powders I have ever burned in 9mm loads is Unique. It gives near 100% load density with all bullet weights and is just plain accurate. Only trade off is, its a little dirty. So if you shoot a stainless gun, itll be black after just a few mags. But the groups will be worth it.

[76Highboy]

Originally Posted by JLA

In a rifle yes, seating depth and how the case is sized makes a difference. With handgun ammo the powder used is the biggest accuracy factor. If you arent getting an accurate load with any charge weight within the recipe for that powder then switch powders. Ill tell you now that one of the absolute best powders I have ever burned in 9mm loads is Unique. It gives near 100% load density with all bullet weights and is just plain accurate. Only trade off is, its a little dirty. So if you shoot a stainless gun, itll be black after just a few mags. But the groups will be worth it.

100% ditto on that. I shoot a lot of Unique. And Bullseye as well.

[JLA]

I use titegroup and bullseye for light bullet 9mm loads. They are both well suited to that end of the chart.

[bntyhntr6975]

Were the LRNs that you tried sized to the correct diameter for your barrel? A lot of people never bother to even check. My best load in 9mm is 124g cast RN ahead of a max charge of Power Pistol. I don't recall overall length right now but I know its close to the listed length. Pistols are not near as picky as rifle as far as seating depth vs. accuracy. Pretty much, find a length that functions well and then adjust the powder tiny bits. Be careful not to seat most pistol loads too short, this can cause severe pressure spikes and you might not get a second chance at it. And since alot of pistol loads have a small amount between min and max, take caution there too. 9mm is alot more forgiving than some others and its a great little round.

[American Leader]

OAL makes a big difference in pressure and velocity which in turn can make a difference in accuracy. When your reloading manuel notes a minimum OAL for a specific load it is telling you not to load this recipe below the stated minimum overall length. Generally that length is best for that load, however, there's a difference between safety and how well a specific load operates in a particular firearm. A reloading manuels information gives specific data and ballpark specific results. You do have some variation to work with as noted to find what shoots best in your gun, but follow your manuel and be very careful when deviating from it. When you start adjusting lengths "OAL" at random, you're looking for trouble. Whatever you do needs to make sense.

[prof_fate]

I know lead bullets are available in different diameters, but .356 is the one that is common and what I got.
I'm using W231 - recomended by many as a versatile and easy powder to learn to work / reload with.
Unique was one I considered as well.

Does crimp have an affect on accuracy? I'm using a lee factory crimp die as it supposedly eliminates any issues with case length variation regarding accuracy.

[American Leader]

Because crimping has an effect on pressure as well, it will keep each rounds pressure more consistent and consistency leads to accuracy.

[prof_fate]

consistency from round to round (be that powder, crimp, length, etc) will make each round consistent to the next. Fine, I get that.

But when I read tests in magazines some ammo groups at 1" and others at 4". I want to make ammo that groups at 1" of course.

So what is the best procedure to follow to get there? If I make 20 rounds and get 4" groups, what do I change first? Length, bullet, powder, primer, crimp?

[American Leader]

prof, I'll send you some info via private message. Give me a little time, it's past bedtime!

[JLA]

Originally Posted by prof_fate

consistency from round to round (be that powder, crimp, length, etc) will make each round consistent to the next. Fine, I get that.

But when I read tests in magazines some ammo groups at 1" and others at 4". I want to make ammo that groups at 1" of course.

So what is the best procedure to follow to get there? If I make 20 rounds and get 4" groups, what do I change first? Length, bullet, powder, primer, crimp?

If youre using an OAL that works in your gun then adjust the powder charge til you hit one that jives. Youll know when you hit it, that little gun will sing and if you know what youre doing behind the trigger it wont miss.

As for crimp, I put a taper crimp on all auto pistol ammo and a roll crimp on all revolver ammo. for 9mm, the casemouth should measure .379 - .380 after crimp.

[carver]

I've been reloading for .45ACP, and .380 in auto pistols for some time now, and I have never had such a problem! Guess that's just me! With lead bullets I put a light crimp at the crimp ring, and what ever the COL comes out to is what I shoot. So far I have had no problems with accuracy, and everything shoots where I point the gun. Now if I wanted to make ultra accurate bullets for competitive shooting, I might be looking at "all" the factors in making a bullet. I make mine to plink with, and the ammo I carry in a SD gun is the best factory ammo I can buy.

[prof_fate]

for IDPA 8" at 15 yards is fine.
To do well in PPC you have to get your shots into an index card sized target at 25 yards from multiple positions.

I'll measure my crimp

[JLA]

Gee whiz, those are pretty big requirements. Pretty much any gun with any good ammo should be able to best those requirements in the hands of a good shooter id think.

[prof_fate]

Originally Posted by JLA

Gee whiz, those are pretty big requirements. Pretty much any gun with any good ammo should be able to best those requirements in the hands of a good shooter id think.

Well, basically you need 2" or better groups...and not off a bench. Reading some of the gun tests in magazines some gun/ammo combos can barely do 8" and most reviews say 2 to 3" groups are acceptable.

The guy that runs teh PPC locally says the best here shoot 6" SW 686.
Out of 60 shots half are shot from 25 yards and 600 is possible. Below 515 is the basically the same as zero. So 50 of your 60 shots have to hit that card-sized space - and that won't make you good, just keeps you in the game. They group you by score ranges, about 10-15 points per range (for the season and team makeup - top range is 590-600 avg for example. ). They run it similar to a bowling league- 20 weeks long, 4 lowest scores get dropped.

I shot this at my last club in a modified form - indoors so 50' was the far range and a round was only 36 shots and small bore was acceptable. I was fair with a Ruger Mk1 target model. So now the distance is 50% farther, prone and sitting are added, it's outdoors, more shots and centerfire - but the same target is used (B27)

The more accurate and consistent the tools the better the score. Yes, being a good shot helps but take a crap gun and even the best shot can't be competitive.

[JLA]

Dang. I need to look into getting into this competition stuff in my area. I never bothered with it because of work, just liesure shooting at my own range when i have the time for it. But 2" groups at 50 yds with my 586 is not uncommon with my handloads.

[prof_fate]

Originally Posted by JLA

Dang. I need to look into getting into this competition stuff in my area. I never bothered with it because of work, just liesure shooting at my own range when i have the time for it. But 2" groups at 50 yds with my 586 is not uncommon with my handloads.

My current club is bit into shooting and competitions - they've got 5 or 6 ranges, some lit,indoor range, youth CMP program, rifle (out to 400 yards), weekly rifle shoots, IDPA monthly, combat weekly, bullseye pistol plus trap and they recently bought a bunch of steel targets so perhaps steel challenge is next. They don't do any cowboy action (hey, were in PA no Tx) and no three gun.

Competition gives you a reason to shoot - motivation to improve and concrete way to measure your improvement - and compare yourself to others. Plus you meet people and make friends. And who knows, you might use it to justify a new gun or two or three...

And the ammo is the most expensive thing. All 20 weeks costs $60 - that includes the targets, awards, trophies and such. So $3/week - like I said, the ammo costs more!

I"m rusty - I last shot in the 80s and other than a mag or cyl in someone else's gun never shot any centerfire. I have till April 18 to get it together for combat, first IDPA is March 11...have to decide if I want to watch (having never seen it before) or jump in the deep end and give it a go. I'm just about immune to embarassment anymore.

Going to Mastercraft tomorrow to get some bullets. They're closer than I thought - the range is 10 minutes from my house and they're maybe 10 or 15 minutes further. Prolly gonna do some jacketed bullets...115s maybe. 147s cost more...ok, sure, call me cheap!

[JLA]

115s will do it, I find the most accurate pills for the 9 mil are 124 grainers, but if you aint shootn bullseye, the 115s will do well.

[prof_fate]

I shot some factory 115s today and was happy. I have some 124s I can pop off tomorrow on the way to the bullet factory.

I have some 115's I can load tonite and try as well. Not exactly the same bullets but the weight is the same.

Maybe I'll take some of the 124s apart and use my powder to test them as well.

So does that make me Dr Frankenstein or Igor? LOL

[JLA]

Dr frankenstien was the man barking orders and taking credit, Igor was the hunchback doing all the work and experimenting..

[prof_fate]

that would make me Igor then...