First Use of Hornady OAL Gauge - Help!

[markr6754]

Ready to start loading 300 Blackout and bought a number of tools in order to do it right. Today, my Hornady OAL Gauge arrived, as well as my modified 300 Blackout Case, my Hornady Comparator w/Anvil base, and my Hornady Case Trimmer.

First things, first...I assembled the OAL gauge, fitted a new Lapua 220gr Scenario L HPBT bullet, and made my first ever test of measuring to the lands. This was closely followed by my 2nd, 3rd, 4th.....20th tests.

I’m measuring 2.350” repeatedly. The only time I get a shorter measurement is when I jam the bullet into the lands and have to push it out again. When I “touch” the lands and lock the gauge, I get the same 2.350” reading. My reading and YouTube views tell me that my most accurate loads will be 0.020” to 0.050” off the lands. In either case, this puts my loads well past the SAAMI max OAL of 2.260”.

I’d appreciate some comments...I picked up 1500 of these bullets (the price was reduced 50% for Christmas). It looks like a fantastic bullet...but do I now have 1500 tiny paperweights?

[hounddawg]

I use 80gn Berger VLDs in my .223 bolt gun, all the common knowledge on the forums say seat them in the lands for best accuracy. Mine does .6 MOA 10 shot groups at 300 yards seated .075 off lands. Don't believer everything you read. Load them and shoot them. Start at .100 off lands and advance them to magazine length and see how they group.

other alternative is shoot them single load

[markr6754]

Originally Posted by hounddawg

I use 80gn Berger VLDs in my .223 bolt gun, all the common knowledge on the forums say seat them in the lands for best accuracy. Mine does .6 MOA 10 shot groups at 300 yards seated .075 off lands. Don't believer everything you read. Load them and shoot them. Start at .100 off lands and advance them to magazine length and see how they group.

other alternative is shoot them single load

Thanks for the response. Of course, if I start 0.100” off the lands I’m in good shape. That would put me at 2.250”, just below SAAMI. I also believe that’s near maximum for AR mags.
Appreciate your comments, but as a brand new reloader, and this, my first, ever, rifle cartridge as well as my first ever AR, I have to read tons. If I stop believing I’m totally lost. I do, however, check 3 or 4 sources. If they all repeat the same thing I tend to buy into it. I won’t be able to discount new learning until I have enough skill and knowledge to stand on my own. You’ll note, however, that I came running to a trusted forum when I hit a snag.

[Nathan]

What rifle?

[markr6754]

.300 Blackout 8.5” pistol build...PSA kit on a stripped Anderson lower. No suppressor. Have 3 10 Round Magpul Pmags, and 2 Lancer 20rd .300 Blackout mags. Barrel only has 10 rounds through it...so I’m ahead of myself. But I don’t want to wait until I need ammo before I load it. I have 65 .223 cases I’m processing, 10 recovered Armscor.300 Blackout cases, and 225 new Norma cases.

[Nathan]

Nice rifle. 2.26” is SAAMI limit because the mags are limited to 2.26”. Making 2.35” ammo becomes a bit irrelevant.might be worth adjusting from 2.26-2.22 to see if there is a sweet spot in there?

[RC20]

Markr: Some of this stuff is just a head scratcher.

The press and die mfgs tell you to set the dies so the ram touches the base and then turn it 1/8 or 1/4 more (cam over)

Sure it works, for 4 to 7 cases then they crack at the base.

So there is a fix to do a minimum shoulder set back (minimum resize) and avoid that.

Al die mfgs tell you the same thing, I would have to check but I think 1/16 wold more than do it. sheese.

Welcome to the club and you came to the right place to (mostly) get good answers.

PM those you like to follow up if you are getting the feeling the info is not right. Not many but some will repeat poor or even wrong info.

[F. Guffey]

Markr: Some of this stuff is just a head scratcher.

The press and die mfgs tell you to set the dies so the ram touches the base and then turn it 1/8 or 1/4 more (cam over)

I could ask; "What does that mean?" Problem: If there was an answer it would sound like members are starting over.

F. Guffey

[std7mag]

I know my answer, but you probably wouldn't like it....

Throw the bloddy thing in the trash bin!!!

Don't have one, don't use one, don't need one, don't want one.
Just a good way to get confused with new gadgets.

[RC20]

Mine is not only a go to, I have all the bullets I use listed for max, load em long and it goes to the range with me so I can adjust as needed.

I use my digital for it as I like numbers showing up that way, they stick better.

To each his own.

[F. Guffey]

Quote:
Markr: Some of this stuff is just a head scratcher.

The press and die mfgs tell you to set the dies so the ram touches the base and then turn it 1/8 or 1/4 more (cam over)

I could ask; "What does that mean?" Problem: If there was an answer it would sound like members are starting over.

F. Guffey

know my answer, but you probably wouldn't like it....

Throw the bloddy thing in the trash bin!!!

Don't have one, don't use one, don't need one, don't want one.
Just a good way to get confused with new gadgets.

I do not agree; the claim insist on turning the die 1/8 to 1/4 turn after contact. That would be .0085" to .017" after contact. Always and forever reloaders express a lack of knowledge when it comes to adjusting the die. And then there is that cute little addition that is placed in parentheses about cam over. If the press is a cam over press the .0085" 1/8 turn or the .017" 1/4 turn has to be added to the amount of cam over built into the press.


If the press is not a cam over press the die is adjusted after contact.

F. Guffey

[LineStretcher]

Not sure if the OP read all the instructions or not. The OAL gauge works very well.

The Hornady case that your bought is an unfired case. It's close but may not correctly fit your chamber and when you're working with such small numbers it makes a difference.

First thing you need to do is commit to a brass manufacturer for you rifle. I happen to like Lapua but the choice is yours. Once you've got your brass, load some up at starting loads with whatever bullet you want. All you're doing is generating once fired brass that fits you chamber.

If you have a lathe you can drill the case and tap it for the OAL gauge. If you don't you can send it to Hornady with a check for 15.00 and they will do the work for you. This will give you a case that fits your rifle perfectly. The only thing you need to do is trim it to "trim length" if needed.

Now that you have a case that is on axis with your bore, you can use the OAL gauge to accurately measure the location of the lands.

There is one Caveat. If your rifle has a lot of free bore (Weatherby's for example) then you should use the recommended COAL and not try to get to the lands. In the case of Weatherby's and some other manufacturers, the free bore is used to swage the bullet to the exact size of the bore before it hits the lands. The COAL in the books needs to be adhered to or you can create excessive pressures.

[RC20]

Weatherby is also a pressure control aspect by keeping it further back from the lands.

[LineStretcher]

Originally Posted by RC20

Weatherby is also a pressure control aspect by keeping it further back from the lands.

This is correct. Roy was a pretty smart guy. I guess he found that if he undersized the bore then swaged the bullet in the free bore, it would use all of the depth of the lands to spin the bullet. Of course, in order to do what he did, he had to come up with the Mark V 200,000 psi action just in case one of his customers got a little too aggressive with their loads.

[cw308]

Your getting consistent measurements with the Hornady OAL gauge , that's good it didn't work well for me , anyway I would adjust 40 off then 20 , 10 , zero .005 jam and see how the group .

[F. Guffey]

This is correct. Roy was a pretty smart guy. I guess he found that if he undersized the bore then swaged the bullet in the free bore, it would use all of the depth of the lands to spin the bullet.

I am the fan of the running start, I want my bullets to have that jump. I do not believe Roy Weatherby swaged the bullet to the free bore. Roy did not want the bullet to slow down when it hit the rifling nor did he want to bullet from starting out at the rifling. I understand that, Roy understood all of that but I have never found a reloader on a reloading forum that agreed.

Reloaders want their bullets stuffed into the rifling with no consideration given to reducing the powder charge.

I am the fan of determining the distance from the rifling to the bolt face.

F. Guffey

[LineStretcher]

Originally Posted by F. Guffey

I am the fan of the running start, I want my bullets to have that jump. I do not believe Roy Weatherby swaged the bullet to the free bore. Roy did not want the bullet to slow down when it hit the rifling nor did he want to bullet from starting out at the rifling. I understand that, Roy understood all of that but I have never found a reloader on a reloading forum that agreed.

Reloaders want their bullets stuffed into the rifling with no consideration given to reducing the powder charge.

I am the fan of determining the distance from the rifling to the bolt face.

F. Guffey

I didn't always agree with it either but after I made a cutaway of a .257 Weatherby Magnum chamber and took measurements, the lightbulb went on and I realized exactly what he was doing and why.

[RC20]

I am the fan of determining the distance from the rifling to the bolt face.

I am a fan of keeping it simple and knowing what my comparator Ogive COOL (case overall Ogive length) .

Fully agreed about not being in the lands though I will test up close.

[mehavey]

300 Blackout ... Hornady OAL Gauge ... Lapua 220gr Scenario L HPBT bullet... I’m measuring 2.350” repeatedly.

Simple.
You have a lot of freebore when using that bullet.

If you want a gut check . . .
- Drop a bullet into the breach,
- Hold in lightly into the rifling w/ a pencil/eraser
- Drop blunt cleaning rod down muzzle to meet bullet. Mark the rod.
- Remove bullet/close bolt/drop rod down to bolt face. Mark the rod.
- Measure distance between marks (Hint: likely to be 2.350-ish)

You're done. Load to max magazine length (2.26"); walk away; live with the bullet jump when using that bullet..

[markr6754]

Originally Posted by mehavey

Simple.
You have a lot of freebore when using that bullet.

If you want a gut check . . .
- Drop a bullet into the breach,
- Hold in lightly into the rifling w/ a pencil/eraser
- Drop blunt cleaning rod down muzzle to meet bullet. Mark the rod.
- Remove bullet/close bolt/drop rod down to bolt face. Mark the rod.
- Measure distance between marks (Hint: likely to be 2.350-ish)

You're done. Load to max magazine length (2.26"); walk away; live with the bullet jump when using that bullet..

This makes a lot of sense. I’ll give that a try. I was doing something like that when using the comparator. I actually used a bamboo chopstick...blunt and soft. Didn’t consider taking measurements. I was only trying to ensure that the bullet was touching the lands.

[Unclenick]

In 223/5.56 it is common for competitors to load the 80 grain Sierra bullets for slow fire at 600 yards. Sierra says to seat them to 2.550" COL. It's 0.330" over SAAMI max, but that's because the ogive is so long its shoulder (where the ogive starts to depart the cylindrical bearing surface portion of the bullet) at the right place for a normal throat. The assumption is simply that you will load them singly and not from a magazine and then they will be fine.

One time I bought some HSM ammunition that used that 80 grain Sierra, but it was not seated to 2.550". It was seated to 2.230". HSM had figured out they could set the bullet shoulder below the case mouth (which this did) and it still functioned fine. You have to watch out for the "dreaded donut" forming at the neck and shoulder junction and ream it out if that happens, but it's no big deal. There is just a lot of bullet jump. But it seems to function just fine.

Berger found out, and I expect this applies to all long-ogive bullets and secant ogive bullets in particular, that in some rifles some bullets don't group well until the jump is over an eighth of an inch. The deep-seated HSM has a good deal more jump than that in a standard chamber, to no particular disadvantage on paper. It is still commercial match ammunition and works as well in my gun as any commercial match ammunition does.

The bottom line: determine what seating depth gives you best accuracy and use that for single-loaded rounds for precision, but don't be afraid of a long jump for magazine fed ammo.

[RC20]

I no longer am and play with quite the range these days.

This site has been a big help in that as well as other aspects.

[Metal god]

My reading and YouTube views tell me that my most accurate loads will be 0.020” to 0.050” off the lands. In either case, this puts my loads well past the SAAMI max OAL of 2.260”.

Yep happens all the time when restricted to mag length . That COAL tool is great when you can use it but as you just found out sometimes it's totally useless when finding the lands means nothing to what you can load to . I'm loading a 308 Berger bullet that is so long I can't eject the loaded cartridge from the rifle because the COAL is to long to clear the ejection port of the receiver . If I chamber it I pretty much need to shoot it or it's a pain to get out . The round just stays stuck in the bolt face grabbed by the extractor and pushed against the side of the receiver by the ejector . It does not even come close to fitting in a magazine . Need to single load those rounds .