Reloading 9mm ?s

[scooterj]

It's not you. That amount of variation is from the bullet shape. They are not all the same.

 

[Sin-ster]

OK I'M having a new issue now. For some reason my OAL varies + or - .005 is this something to worry about?

Provided you have allowed yourself enough of a "buffer zone" in terms of lead (the distance the bullet must travel between the case and where it contacts the rifling), it's not a huge concern for your application. It may not even result in degradation of accuracy, for that matter.

However, an ES of .010 is pretty high, which is what I think you're getting. (Even .005 would bug me.) The Dillon manual, for example, allows for an ES of .004, based on variations in cases and projectiles. That may be a conservative figure-- scooter's been loading 9mm a lot longer than I have! However...

Using 124 grain JHP's from Montana Gold, and strictly Federal brass, my ES is .0025; my SD is probably below .001, by my rough calculations.

There's numerous things that could account for your variations, and we can go over them if you decide it's worth sorting out. Risk of touching the rifling aside, it's not something to worry about-- but it's not exactly "normal" or common either.

If you're using mixed brass, that's probably accounting for a lot of it. Depending on the projectiles you're using, it could indeed just be a matter of the components. Take your calipers to a random selection of each element and see what you come up with. If they're all pretty uniform, you'll know that something else is going on.

 

[bigtattoo79]

What is the right way to check how close I am to the the rifling?

Edit to add: Sin-ster it is only .005 off if I set my OAL to 1.145 I get stuff like "1.143-1.148".

 

[Tulse Luper]

Edit to add: Sin-ster it is only .005 off if I set my OAL to 1.145 I get stuff like "1.143-1.148".

Measure a few from a box of WWB to see just how good that is.

 

[Sin-ster]

What is the right way to check how close I am to the the rifling?

Edit to add: Sin-ster it is only .005 off if I set my OAL to 1.145 I get stuff like "1.143-1.148".

Grab a handful of fired/unsized brass and a handful of projectiles. Of that lot, you'll get a few bullets that will slide easily into the case, but have enough neck tension to not slip-slide around under the force of gravity. Leave them seated extremely long-- just enough to keep the projectile steady within the case.

Put 3-5 of those together, remove the barrel from your pistol, and drop them in one at a time. Gently apply pressure to the case head until the cartridge is fully chambered; it won't compress any further at that point, so don't force it. Even more gently, remove the cartridge and take an COAL measurement. Looking at your data pool, you'll have a pretty good idea of how long the case can be to still chamber, but be touching the rifling. Some folks say to average the numbers-- I would personally take shortest COAL and call it my "max", just to err on the side of caution. If you've got really dramatic ES from this test, use it only as a starting guideline, and perform the following procedure:

Run a single case through resize and belling-- don't add a primer or powder. Start with the longest COAL from your first test and seat the bullet at that depth. If you're not overbelling, this will work without crimp-- and keep you from wasting components. Drop-check the cartridge in your barrel and see if it chambers all of the way; you'll hear a nice hollow "plunk", and the it will be visually obvious. Try to spin the bullet in the chamber-- if it moves freely and drops out freely, you're still off the rifling. Pull the bullet or start with another case/projectile and go longer. Your goal is to find the length at which the round would chamber, but is touching the rifling-- a no-go in terms of a hot round, but it establishes the point at which you're running into trouble.

Subtract .010 to .015 from that touching-the-rifling length, and you've got what I consider to be your max/ideal COAL. Keep in mind that depending on the consistency of your projectiles and brass, these numbers can vary. Ideally, you'd find the "longest" combination (which would give you the *shortest* COAL) and use that as your baseline. Every time you change projectiles (and not just type, but brand as well) you'll want to repeat this step, as the profile will determine at what length you start getting into the rifling.

Even using mixed brass and projectiles with a lot of variance in terms of their size and shape, the .010-.015 cushion you've allowed yourself should give you a large enough safety margin to never have to worry.

An ES of .005 could quite easily be a matter of your components, and not the press itself or something about your process. For point of reference however, I found the single biggest detriment to consistent COAL was too much bell prior to seating. If you have to hold 1 out of every 500 or so in place until it's almost inside of the seating die, you're probably doing it right; there should be just enough bell for the projectile to sit on the case, and any more can cause you problems.

 

[Sin-ster]

Just for reference, here's the reasons why I can eek out such consistent lengths:

1) High quality projectiles. MG's of all flavors are very consistently formed, and JHPs will be more consistent than FMJs due to the construction process.
2) Sorted brass. No matter what headstamp you choose, keeping them separated will make a difference. Less important is "times fired" sorting, but it can't hurt your consistency!
3) Redding Competition Seating Die. This thing is the bomb-shizzle, and the micrometer setting makes adjustment to OAL both precise and easy. The universal stem it uses is amazing.
4) Clean Brass. You ain't gotta eat off of it, and it doesn't have to look new, but any crud or build up can cause you problems.
5) Hornady One Shot. Easier on the press, easier on your arm, and it makes for a more consistent stroke.
6) Smooth stroke. Quick, careful-- whatever your method, be sure it's smooth and repeatable every time you run the ram.

Those are the "me-specific" things. As previously noted, you should make sure you're using the right amount of bell. Combination seating/crimping dies are problematic. The press should of course be mounted sturdily to your bench (I know yours is-- I've seen the photos), but it may be necessary to further anchor the bench to prevent movement. On a progressive, a shell in every station is key-- you'll get different lengths otherwise; the resizing/decapping station seems to be the most important on my 650. The proper seating stem (duh) should be used. A clean-ish and properly lubed press is vital.

 

[bigtattoo79]

Sin-ster Thanks for the great info its been a big help.

If I take the longest round I can find outta 300 rds that I presed the closest it comes to the rifling is .006 so I need to work on it a bit more.

 

[Sin-ster]

Sin-ster Thanks for the great info its been a big help.

If I take the longest round I can find outta 300 rds that I presed the closest it comes to the rifling is .006 so I need to work on it a bit more.

I'd add a tiny bit more cushion to that, for peace of mind.

It's important to remember that if you go way past the point of contacting the rifling, the round almost certainly won't chamber. (If it does, it'll be set back in the process-- which makes your problem even worse. But that's pretty uncommon, provided your bell and crimp are adequate.)

That means the closer you cut it, AND the more consistent your COAL... the more likely you are to wind up with a pressure issue.

 

[bigtattoo79]

I'd add a tiny bit more cushion to that, for peace of mind.

It's important to remember that if you go way past the point of contacting the rifling, the round almost certainly won't chamber. (If it does, it'll be set back in the process-- which makes your problem even worse. But that's pretty uncommon, provided your bell and crimp are adequate.)

That means the closer you cut it, AND the more consistent your COAL... the more likely you are to wind up with a pressure issue.

So it "could" be unsafe to shoot the rds I have loaded?

The load is:
135 gr Bayou Bullets
4.0 gr of WSF
1.145 OAL

I will add I have load data for:
135 gr Bayou Bullets
4.0 gr of WSF
"1.105 OAL"

So my thinking is that the bullet could be set back .040 more and still not over pressure Im I correct on this?

 

[Sin-ster]

So it "could" be unsafe to shoot the rds I have loaded?

The load is:
135 gr Bayou Bullets
4.0 gr of WSF
1.145 OAL

I will add I have load data for:
135 gr Bayou Bullets
4.0 gr of WSF
"1.105 OAL"

So my thinking is that the bullet could be set back .040 more and still not over pressure Im I correct on this?

If you measured the distance to your rifling, and then specced all 300 of the rounds you have loaded, you should be good to go on those. For extra safety, you oughta pull the barrel out of your gun and drop check them all-- listen for the hollow "tink" of the round chambering, then give it a spin to make sure there's no resistance (indicating contact with the lans and groove). It should also drop free under the force of gravity alone. If they all pass, shoot 'em up-- you'll be fine (and you're working under optimum feeding length t'boot).

In the future, with the ES you're experiencing, you may wanna pull them back a little bit. I'd say if your longest round out of that 300 is .006 from the rifling, you might wanna drop your target OAL .010 more (with the type of ES you're getting). It's not going to cost you anything, but you'll pick up peace of mind.

If there's a published load for 4.0 grains of WSF @ 1.105 OAL, then you've got a lot of room to work with. .040 is quite a bit of drop however, and you might be getting more pressure, and subsequently higher velocities than are necessary to make PF-- but the round is still safe. On top of that, reducing the length that much is a bit excessive for the sake of safety.

Take several (25 is plenty) of the 300 you have loaded and put them over the chrony, recording your results. Drop the length on the next batch by .010, and repeat the process. You almost certainly won't see much of a difference, if any-- but it's the only way to know for sure.

As always, check for pressure signs on your spent brass. Flattened primers are typically the earliest symptom, and easy to spot; if you're getting bulged brass, it's gone WAY too hot. You may also experience rough extraction as the pressures become borderline, which you'll not only be able to see in terms of damaged rims and retarded ejection patterns, but you oughta be able to feel it as well. My bet is that you're no where near the "trouble zone", though-- but it's good to know for sure!

FWIW, the 9mm case itself is extremely tough in the grand scheme of things, especially at the case web where most of the really scary failures occur. Remember, the Open guys are running 9 Major in the same case as you're running minor; it requires a purpose built gun/chamber/barrel of course, but the case itself can stand up to that torture. That's NOT free license to get silly of course-- but it should at least make you feel a bit better!

 

[bigtattoo79]

Sin-ster
It seems like I messed up the 1st time I measured the distance to my rifling. It looks more like I have .015-.020 but I will test it more to make sure.

Dont you have a M&P Pro? I know mine "wont" be the same but whats your max distance to your rifling?

 

[Sin-ster]

Yeah, testing for mine was a bit touchy as well; I got some pretty inconsistent results, and continue to do so as I check each new lot of ammo.

Ultimately, I loaded one really long (with barely any bell) and drop checked it in the barrel over and over, reducing the OAL each time it sat on the rifling until it was fully chambered and still unable to spin freely.

Keep in mind-- the bullet profile you're using is vastly different from mine. My distance to the rifling and yours probably won't be the same as a result, in one direction or another; that's why it's important to test for yourself.

That said, I found with the Montana Gold 124 grain JHPs, I'm fully chambered AND hitting the rifling at 1.151; I load to 1.140, and my ES is no more than .003 (so + or - .0015).

 

[flamatrix99]

ok what is ES?

 

[Sin-ster]

Extreme Spread.

The difference in length between the shortest completed cartridge and the longest.

Truth be told, I'm not sure it's used very often in this regard. But it appears on my chrony, so I decided to transfer it over to other aspects of reloading!

 

[flamatrix99]

I just started reloading .223 these last couple weeks on my 550B. Last night I finished up the last of my 77 gr SMKs. As I was seating the bullets most OALs were within ~0.002". I figure not bad. Some were spot on to the OAL I wanted. A couple pissed me off and were 0.005" different.

For sh*ts and giggles I busted out a box of WWB .223 and started measuring thier OALs. WOW that was quite eye opening. Out of the 4 that I measured the ES was roughly 0.016". I was loading my SMKs to 2.260" and the WWB were loaded to 2.210". They were only 55 gr but they were loaded .050" shorter then I loaded mine.

 

[davidd]

So... how do it know?

The chronograph, that is, which cartridge is longer, shorter, etc.?????

.

I believe he meant that the ES field is available on the chrony for velocity, so he decided to record it (manually) for the load lengths. Not that the chrono actually could calculate it for the load length.

 

[Sin-ster]

So... how do it know?

The chronograph, that is, which cartridge is longer, shorter, etc.?????

.

I meant just transfer the term over. It gets used a bit in velocity/PF discussions; I just wasn't sure how often it come up in terms of cartridge measurements.

Pretty bad wording for an English Major, I guess...

 

[Sin-ster]

I just started reloading .223 these last couple weeks on my 550B. Last night I finished up the last of my 77 gr SMKs. As I was seating the bullets most OALs were within ~0.002". I figure not bad. Some were spot on to the OAL I wanted. A couple pissed me off and were 0.005" different.

For sh*ts and giggles I busted out a box of WWB .223 and started measuring thier OALs. WOW that was quite eye opening. Out of the 4 that I measured the ES was roughly 0.016". I was loading my SMKs to 2.260" and the WWB were loaded to 2.210". They were only 55 gr but they were loaded .050" shorter then I loaded mine.

It's the same for WWB pistol cartridges as well.

Before I got the "system" down and had some fairly big swings in OAL, I performed the same test. It definitely gave me peace of mind.

Of course, having seen rounds come out of those white boxes where the projectile had sheared the neck open far enough to spill powder into the packaging... I decided I'd hold myself to a higher level of QC.

 

[bigtattoo79]

OK It does seem that "as Sin-ster said" my inconsistent OAL is "for the most part" from mixed brass. Thanks for the help everyone!!