Finding data for true OAL....?

[redneckmedic]

When loading for rounds without a flat nose its very difficult to find / measure a true OAL. But as I've written before other than mag length OAL doesn't really matter. But all data in the loading manuals ia based on OAL. Pistol, I really don't care, if it fits in the chamber or go/no go die I'm g2g. But my rifle is a different story, I'm loading 308 A-Max and that little plastictip is worthless to measure off of. For my bolt I've got a round set with a lock-n-load so that's easy to measure off with my bullet comparator gauges. But if I want to find a consistant length in my 308 I cantfind an OAL off a round, nor ue the length measured from the comparator and compare either to a suggested OAL data.

Not that any of this really matters, I'm loading to mag length and ogive - 0.002 anyhow, but it is odd how there is no way of finding true OAL in comparison to the data. I thought that maybe the comparator guage was 1" long which would make the math easy... but no dice.

 

[Yeah]

Length to ogive is what matters, as it is an indicator of the bullet's distance to, engagement of or in, the barrel's lands.

Of secondary consideration is that either measure can be used to determine the cartridge capacity encroached by the base of the bullet, though when talking variation in the thousandths/hundredths there is little effect on pressure.

By extension no manual has any idea where your lands are in your specific rifle. Finding the location of those is key if you can get a bullet into them and still fit the mag box. Building a dummy cartridge indicating that placement is the quickest way to get set up for subsequent reloading sessions, as that dummy can be placed in the press and the seater screwed down to contact its ogive, and you are ready to roll.

When loading to fit a mag box I find something closer to 0.05" wiggle room to be more reliable.

 

[shibumiseeker]

Yeah gives the basic correct answer. Don't drive yourself crazy with it. First consideration in a gun with a magazine is to load to mag length maximum minus a hair. Second consideration is how you want your jump to the lands (if any). Reloading is both an art and a science.

 

[noylj]

I think it may have been "easier" in the past when manuals did NOT list a COL. At that time, it was known that COL was so dependent on the gun and magazine that each reloader had to determine the COL for themselves. This is still true, but so many reloaders now seem unable to grasp that COL is not something that can be handed down from on high.

 

[Leo]

A typical season for me used to consume one barrel in the across the course rifle and one barrel in the long range rifle, so chasing the lands as they wore was a regular deal. There was an entire set up from a company called stoney point. All measurments were at the bullet ogive or the throat, so it only gave you the info for the barrel mechanical realities, you can get magazine limits simply by looking at it. The system made it very easy to know the true distance to the lands with the exact bullet you are going to use in your loads. It worked great. Adding a Redding micrometer style bullet seater to your reloading dies made it easy to track throat wear and compensation. I think Hornady bought stoney point and still sells the setup.

 

[Broom_jm]

Reloading is both an art and a science.

What an artful, and scientifically accurate, statement! If only double-reps were allowed.

I think it may have been "easier" in the past when manuals did NOT list a COL...so many reloaders now seem unable to grasp that COL is not something that can be handed down from on high.

Also an accurate statement, and somewhat of an unnecessary indictment of fellow reloaders? For many situations, using an exact recipe, loaded to an exact OAL, is precisely what should be done. Certainly no need to castigate those who don't fully understand other means of determining OAL in their firearm.

A typical season for me used to consume one barrel in the across the course rifle and one barrel in the long range rifle, so chasing the lands as they wore was a regular deal. There was an entire set up from a company called stoney point. All measurments were at the bullet ogive or the throat, so it only gave you the info for the barrel mechanical realities, you can get magazine limits simply by looking at it. The system made it very easy to know the true distance to the lands with the exact bullet you are going to use in your loads. It worked great. Adding a Redding micrometer style bullet seater to your reloading dies made it easy to track throat wear and compensation. I think Hornady bought stoney point and still sells the setup.

Yep, Hornady sells the exact same setup, giving it their ubiquitous, if somewhat nebulous, "Lock-n-Load" (LNL) labeling. I don't know of an easier or more accurate way of determining the maximum OAL to use in a given firearm, but I've always used simpler means that produce great results.

In a semi-auto pistol, your barrel makes a perfect case length gauge. In a rifle, a bullet tip covered with black magic marker will tell you when you're engaging the rifling and need to seat back a bit further. If I ever got into bench rest shooting and wanted to chase the throat of a barrel, I'd definitely buy the LNL gauge from Hornady. For "regular" shooting of pistol or rifle, it's just one of those things that are nice to have.

 

[kludge]

I'm sitting here looking at my 20 year "old" reloading manuals (Lyman 47th and Sierra 3rd) and they both list COL for each cartridge. But it's fairly predictable, in many cases (no pun intended) it's 2.800" for short action and 3.340" for standard length action.

The most important thing for us reloaders, as mentioned, is not the actual COL or OAL (whichever abbreviation you choose to use), it's consistency and what shoots best in your rifle.

One caution: be very careful working up loads if your COL is LESS than what is listed for the cartridge in the manual.

That said, I do measure, and I don't use any gauges. My rifle is my gauge. If it chambers, and fits and feed from the magazine, and is not less than the listed COL, then I go by what the target and chronograph say is the best load for my rifle.

I also make a dummy round with each bullet. This way there is no guessing when setting up my dies.

 

[redneckmedic]

I also make a dummy round with each bullet. This way there is no guessing when setting up my dies.

Is this done as simple as putting the round in the shell holder, Max out the ram, the screw the die down to make contact with the bullet?

I ask in true ignorance... that's how I do it, but I wasn't sure if tension created a +/- 0.00? Of change and the rule was all the above then a quarter turn or something.

 

[Leo]

A dummy is simply that, Take an up primed case with no powder, size it and seat a bullet in it at your carefully measure depth. Crimp it slightly if that is your style.

The COAL measurements in the reloading manuals are generally simply SAMMI spec for standard SAMMI chambers, they are not really designed for a particular barrel.

When I had a custom chamber reamer made to my design for .223 in an AR based match rifle, there was 4 or 5 other pattern reamers in the catalog. I'll bet there are at least a dozen now. Most patterns are compatable with SAMMI spec ammo, but not all are. My Pattern was definately not compatable with Sammi spec. That could be dangerous if the rifle would get into the hands of someone that didn't know, so most companies will not make them like that.

 

[kludge]

'neck... yes pretty much that's it, but I'll post my process for a bolt rifle. Bullet seating doesn't require near the leverage that resizing does so you don't have to worry about any press stretch (well I don't anyway).

Making the dummy... This takes some time, but you only have to do it once for that bullet/cartridge combination and never again.

1. No primer or powder, resized case trimmed to correct trim length.
2. On the bullet seating die, back the seating stem almost all the way out.
3. Screw the die into the press just one or two turns.
4. Put the case in the press. (no bullet yet)
5. Raise the ram.
6. Screw the die in until the die makes contact with the case or bottoms out on the shell holder.
7. Back the die out 1/2 turn - I don't want the die putting any kind of crimp on the bullet. This setting is not critical.
8. Lock the die down with the lock nut.
9. Put a bullet in the case and raise the ram.
10. Screw in the bullet seater until you feel contact with the bullet.
11. Lower the ram.
12. Screw the bullet seater in a little - just enought get the bullet seating started.
13. Take the cartidge out and measure with calipers.
14. Screw the bullet seater in a little more. Raise the ram and seat the bullet deeper.
15. Repeat steps 13-14 until you get to ~0.25" to 0.30" longer than the COL of the cartridge.
16. Attempt to chamber the cartridge, don't force it.
17. If it doesn't go, screw the bullet seater in a bit more. go slowly, like 1/8 turn of the seater at a time.
18. Put the cartridge back in the press and seat the bullet a little deeper.
19. Repeat steps 16-18 until the catridge JUST chambers. Don't force the bolt closed.
20. Take and measure the COL. Write it down. (for my .308 Win it's ~2.920" with a 168gr SMK)
21. Subtract 0.015" to 0.020" from that number. You're looking for a COL within that range to start load development. This will put the bullet ogive (pronounced OH-jive) 0.015" to 0.020" off the lands.
22. Screw the bullet seater in 1/8 turn or less - go slow.
23. Put the dummy cartridge in the press and raise the ram to seat the bullet slightly deeper.
24. Take the catridge out and measure.
25. Repeat steps 22-24 until your COL is with the range you calculated in step 21.
26. Mark your dummy round, put it in a baggie with a piece of paper, Note the cartridge, bullet, rifle, and COL and the distance from the lands. DFL= the number from step 21 minus the current COL.
27. If you want to (totally optional) you can use a Lee Factory Crimp Die to crimp the bullet in place to make sure it doesn't move on you in the future.

Once you get a load that shoots you can play with the COL to see if you can tighten up the group any more, but most of us aren't that good or shoot enough rounds to notice. I'm certainly not one of those people.

To reset the seating die using the dummy round...

1. Back out the bullet seater all the way.
2. Put the dummy round in the press.
3. The lock nut usually won't move regardless of the bullet you are using, but if it does... do steps 4-8. Otherwise go to step 9.
4. Back off the lock nut.
5. Raise the ram.
6. Screw the die in until it makes contact with the case.
7. Back the die out 1/2 turn.
8. Tighten the lock nut.
9. Raise the ram and screw the bullet seater in until it make good contact with the bullet. Don't over do it.
10. Put your dummy away and make a new round.
11. Meaure to see if it's still at or about your desired COL, then start loading. My .308 Win likes 2.900" and fits and feed from the magazine just fine.

A number between 0.015" to 0.020" off the lands gives you a few thousandths either way and still be in the optimal range for most bullets and rifles -- again most of us aren't good enough to notice the difference, and no equipment is needed.

If you're a real tweaky benchrest shooter then get the tool, otherwise this method has been working for me for several years.

 

[Yeah]

My process is roughly the above, though my initial seat is to mag box length - 0.05" because that is the longest I'll go. If I that is the closest I can get a bullet to the lands I'll suffer it. Remington's 7mm barrels are always throated nicely, their 0.243"s hit and miss, and the 0.224"s more miss than hit.

I'll also have painted the seated bullet from ogive to case with black marker to indicate land engagement and my step 19 ends with me looking for those lands making square marks in the marker. Further seating adjustments are intended to get that square shape and, when achieved, I'm done.

 

[tenring]

Hornady Lock-N-Load Overall Length Gage Bolt Action