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OAL Guage - Why?

Woolsocks

Sergeant of the Hide
Full Member
Minuteman
Oct 24, 2023
103
33
Washington
Is there a benifit to finding the lands with an OAL guage? What does it do, compared to just seating a bullet long and pushing it into the chamber?
 
Jamming causes pressure spikes, it can affect velocity spreads negatively, and it takes effort. In some combos(light neck tension) the throat will hang on to the bullet when you extract a live round and stop the gun due to bore obstruction and powder spilled everywhere. Even when jamming it would wise to know exactly how much you're jamming, which would necessitate finding the “touching” OAL with a tool/method anyway.

Some guys like to jam, and some bullets prefer it. Its up to you to test it. If I had a bullet type that wanted to be jammed, I’d switch bullets.
 
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If you are referring to a Hornady (or Possum Hollow) OAL gauge then that is the easiest way to find "jam" in my mind. There are other tools or techniques that will do the same thing but are different (Sinclair is an example).

There is a learning curve using the tools but that just my explanation. I typically will measure 3 bullets from a particular lot a couple times each. It doesn't take a lot of time as everything is set out and ready to be used with a notebook in hand...

Unlike Supersubes, I don't mind using a Berger VLD (I'll assume that was an example of a bullet he was referring to). That said, I rarely even bother with a VLD in an AR rifle as there a better and easier options for that IMHO. For my boltguns, a VLD bullet will always be available for use.
 
If you are referring to a Hornady (or Possum Hollow) OAL gauge then that is the easiest way to find "jam" in my mind. There are other tools or techniques that will do the same thing but are different (Sinclair is an example).

There is a learning curve using the tools but that just my explanation. I typically will measure 3 bullets from a particular lot a couple times each. It doesn't take a lot of time as everything is set out and ready to be used with a notebook in hand...

Unlike Supersubes, I don't mind using a Berger VLD (I'll assume that was an example of a bullet he was referring to). That said, I rarely even bother with a VLD in an AR rifle as there a better and easier options for that IMHO. For my boltguns, a VLD bullet will always be available for use.
I like bergers, and they make plenty of hybrid ogives which jump just fine.
 
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Jamming causes pressure spikes, it can affect velocity spreads negatively, and it takes effort. In some combos(light neck tension) the throat will hang on to the bullet when you extract a live round and stop the gun due to bore obstruction and powder spilled everywhere. Even when jamming it would wise to know exactly how much you're jamming, which would necessitate finding the “touching” OAL with a tool/method anyway.

Some guys like to jam, and some bullets prefer it. Its up to you to test it. If I had a bullet type that wanted to be jammed, I’d switch bullets.
To clarify. I’m asking why one needs to buy a tool to find the lands. Some people find it by seating a bullet long in a dummy round and chambering it. Why spend money on a tool when there’s simple and free method?
 
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To clarify. I’m asking why one needs to buy a tool to find the lands. Some people find it by seating a bullet long in a dummy round and chambering it. Why spend money on a tool when there’s simple and free method?
If you think stripping your bolt down and doing incremental seating a bit deeper to find seating depth where the bolt handle just drops (which I believe is best how to do this vice just jamming a bullet into the lands and pushing it back into the case) to be more simple, go for it.

Me....I use a Hornady gauge.
 
I like bergers, and they make plenty of hybrid ogives which jump just fine.
I was taking a shot in the dark of what bullets prefer a jam that you might have been referring to. VLD's can jump but jamming works every time for me. I agree completely about jumping hybrids. I can jam a hybrid and they work great but ran out of magazine length in a 6.5 Creedmoor that has an Obermeyer barrel and now jump them a contry mile and the groups are just as good.

I got caught in the "assume" trap but the ass was just me.
 
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To clarify. I’m asking why one needs to buy a tool to find the lands. Some people find it by seating a bullet long in a dummy round and chambering it. Why spend money on a tool when there’s simple and free method?
No reason you can't do it that way. If you also like to know your measurements in an AR, that technique becomes more problematic.

Like Baron23, I prefer a quicker route that also gives good results. I write all my data down for each rifle and check whatever bullet I may use when new (I do standardize pretty quick though). I check the bullets again at certain round counts for throat wear. This applies more for VLD's that I jam in bolt actions (call me a land chaser for certain rifles). That is why I prefer the Hornady tools and I also hate money and don't mind spending it.
 
To clarify. I’m asking why one needs to buy a tool to find the lands. Some people find it by seating a bullet long in a dummy round and chambering it. Why spend money on a tool when there’s simple and free method?
I see now. The answer is simple, tools are way faster and simpler. I use a sinclair tool.
 
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I was taking a shot in the dark of what bullets prefer a jam that you might have been referring to. VLD's can jump but jamming works every time for me. I agree completely about jumping hybrids. I can jam a hybrid and they work great but ran out of magazine length in a 6.5 Creedmoor that has an Obermeyer barrel and now jump them a contry mile and the groups are just as good.

I got caught in the "assume" trap but the ass was just me.
Its all good man. I had my day with VLD’s, both Berger and JLK. Still have thousands of the JLK’s. Im pretty much to the point where i dont do seating depth tests at all, and I can get away with that using tolerant bullets.
 
If you use a case with split neck that holds a bullet lightly you can get maximum OAL pretty quick.
 
To clarify. I’m asking why one needs to buy a tool to find the lands. Some people find it by seating a bullet long in a dummy round and chambering it. Why spend money on a tool when there’s simple and free method?
Depends on your idea of simple or free.... having options and choices is better than no choices....

If you have been in this topic long enough, you should eventually try all the different methods and know the pros and cons of all of them and then decide in what context each one is best.

When introducing new techs and engineers to internal ballistics, we intentionally used multiple methods in the same chambers and in multiple contexts to allow them to learn how "fuzzy" these measurements can be, then we let them follow the life of several different weapons and barrels to learn the importance of seating depth in each context.

I always recommend keeping that dummy reference round for each bullet type, and for those who have the inclination, the drill and tap to make your own tooling case from fired brass is a good thing too. YMMV
 
To clarify. I’m asking why one needs to buy a tool to find the lands. Some people find it by seating a bullet long in a dummy round and chambering it. Why spend money on a tool when there’s simple and free method?
Because bullets stick in the throat, pull back out of the case a little or completely when extracting it and give you numbers that aren't right. You can sort of do it blackening/bluing the bullet to leave witness mark of it's deepest seating, but even that is iffy and a pain in the butt.

I used all kinds of crazy methods years ago, and the the tools on the market now are miles better and Hornady one is dirt cheap for the headaches it saves.
 
Because bullets stick in the throat, pull back out of the case a little or completely when extracting it and give you numbers that aren't right. You can sort of do it blackening/bluing the bullet to leave witness mark of it's deepest seating, but even that is iffy and a pain in the butt.

I used all kinds of crazy methods years ago, and the the tools on the market now are miles better and Hornady one is dirt cheap for the headaches it saves.
This is the best answer to the op question. We’ve all done the partial size or split neck and sharpie methods. The OAL gauges make this process simple and consistent vs the old methods.
 
And if it doesn't have a bolt? :D

You can do the same thing with a barrel held vertical and gravity. The "Speedy" method. No bolt required.

You can also do the "Cortina" method with lube/wax on bullet and chamber it long and use your bolt action bolt or your bolt carrier to send it into the rifling. The lube/wax will almost always keep it from sticking. Then you just back off .020 and now you're in the rifling pretty much as far as you can go without sticking a bullet (you found the stick point with the lube, and backed off). Still in the lands, but not going to stick the bullet.

And of course you can use OAL gauges and modified cases. Which are pretty hard to get exact measurements with since you can push a bullet .005 or more into rifling with very little pressure from your fingers.

Then there's tools like the Sinclair. Methods like using a dowel/rod and bullet.....etc, etc, etc.

As @RegionRat stated above, knowing as many of the methods as possible and their shortcomings is the best course of action. None of them are inherently better than the other overall. There may be a better method/s for your individual situations.....but almost never a one size fits all.
 
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Wheeler method. Scroll down to the finding lands video. Pretty much impossible for the lands to grab the bullet at the touch point and move it.

Swing and a miss, as usual . Give credit where credit is due...Just like Alex did .

Alex wrote..."So far as I know this method started with Leo Anderson and Tom Mousel, at least thats where I learned it. I just made the video... but I am glad its helped."
 
You can do the same thing with a barrel held vertical and gravity. The "Speedy" method. No bolt required.

You can also do the "Cortina" method with lube/wax on bullet and chamber it long and use your bolt action bolt or your bolt carrier to send it into the rifling. The lube/wax will almost always keep it from sticking. Then you just back off .020 and now you're in the rifling pretty much as far as you can go without sticking a bullet (you found the stick point with the lube, and backed off). Still in the lands, but not going to stick the bullet.

And of course you can use OAL gauges and modified cases. Which are pretty hard to get exact measurements with since you can push a bullet .005 or more into rifling with very little pressure from your fingers.

Then there's tools like the Sinclair. Methods like using a dowel/rod and bullet.....etc, etc, etc.

As @RegionRat stated above, knowing as many of the methods as possible and their shortcomings is the best course of action. None of them are inherently better than the other overall. There may be a better method/s for your individual situations.....but almost never a one size fits all.
I found that after a bit of practice, I got very consistent results and any outliers from errors in my using it are very apparent in a series of measurements.

And yes, you can pull the barrel and do the Speedy method (sorry, I had Wheeler method typed originally but I'm easily confused! haha) but I haven’t found it necessary to go to that length in order to get a good reading. But, I’m no expert and defer to those who are.
 
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To clarify. I’m asking why one needs to buy a tool to find the lands. Some people find it by seating a bullet long in a dummy round and chambering it. Why spend money on a tool when there’s simple and free method?
I started doing the blank dummy round and then backing it off .002-.003. Haven't had a chance to try the rounds.
 
Been a good while since I've looked over this thread and some of the videos, etc on this subject.

I still use the Hornady OAL gauge and continue to find that by taking a series of measurement I see great consistency and the ones that are not consistent are very obvious outliers.

And I am familiar with Speedy's vid with Eric Cortina on pulling the barrel and seating a bit deeper iteratively until the cartridge drops in freely to the chamber and there is no resistance to backing it out with your finger nail. But I don't routinely pull barrels, I'm not a competitor of any sort and certainly not a BR or F-Open guy like Speedy and Eric. However, I have a barrel out to be spun up for my first pre-fit action...a CDG. So, I will get this barrel back with no action attached and I'll give Speedy's method a go. Hopefully using sized cases that were originally fired in a different barrel (SAAMI, however) will not give me any issues. I don't think it will but its something to watch out for, right?

I've also seen Both Alex Wheeler's vid and Greg Dykstra vid which seemly appear to be the same method of stripping the firing pin and ejector (for spring loaded ejectors in the bolt vs mechnical ejector as part of the action body) and iteratively seating the bullet in a dummy cartridge until...well, here is where nitpicking my question arises:

Alex Wheeler focuses on seating until the click from primary extraction on bolt handle lift goes away and didn't emphasis the bolt handle dropping freely. Dykstra seems to focus on the bolt handle dropping without resistance but...unless I misunderstood....but he still seemed to have some click from primary extraction.

Yeah, this is way down in the noise hairsplitting and I'm not a BR shooter. But, what the heck, its been raining all day and I'm bored.

But am I misunderstanding Wheeler vs Dykstra (and no I really don't want to get into the Dykstra bashing arena...its been beaten to death already! haha).

Anybody have any insights or suggestions on what may or may not be the better indicator?