I have a thread over in medium bores on my 358 Norma (https://forums.accuratereloading.com/eve/forums/a/tpc/f/3221043/m/5491048362)

But have a specific bullet seating depth question here.

I mention in the thread above that I still need to test the 250 gr Partitions. Well, I did have them loaded and took them to the range, but they would not chamber. The bullets where seated too long. No issues with the Woodleigh, Barnes, and Norma Oryx loads. All set to different depths obviously.

I have never had this problem before. Why? Because I measure all of my rifles and all of my bullets with the Hornady tools. I have NEVER had an issue and have always been spot on.

I checked my notes when I originally measured the various bullets, 3.353" for the 250 gr Partition. I was seated at 3.330". So I measured my loaded rounds. 3.330". I measured my chamber again, 3.353". All bullets where from the same box. I tried all loaded rounds, none would chamber. Measured several bullets from the box in the chamber. Same result. Brass is all new and resized.

So I started trial and error - increasing seating depth until it would chamber. Turns out it was 3.305. I went ahead and cranked it down to 3.260", what Nosler has in their load manual (online data).

Any idea what the heck was happening? I have never seen this.

Are you measuring to the ogive or tip?

quote:

Originally posted by MyNameIsEarl:
Are you measuring to the ogive or tip?

That was my first question too . . . but the OP says he used the Hornady tool to measure both chamber and bullets (I think he means cartridges, because he states values of 3+ inches).

I'm wondering if the bullet-contacting area of the insert was larger or smaller than spec. Just a WAG.

If he's using the Hornady modified case in the tool, he should be able to figure out what the OAL "could" be and then seat 20 to 100 thousandths or so deeper. (whatever shoots best in his rifle and whatever fits the magazine box))
IF the OP has done all that and the ammo is not fitting, it could be the seater die BODY is set too low and he's trying to crimp on the bullet, thus causing the neck to pooch out. I've seen this many many time!
As in, guy's sized brass fits fine. OAL is fine but it won't chamber once seated.

OP, check your brass length once sized and the interface of sized brass with the seater die body where it starts to crimp.
It moght be as simple as backing off the seater die and reset the seater plug to get correct OAL.

Just another thought,
Zeke

I have only load cup and core bullets, and use an unsized fired case to set my seating depth. I hand crimp the neck slightly by pressing into the bench or other handy hard surface to the extent a bullet can be pushed into the neck with enough tension that it doesn't move easily. Then hand push a bullet that I will be loading into said crimped case neck, and then carefully chamber this dummy round into full lockup in the rifle that will shoot these rounds. Then I carefully extract the dummy and measure overall cartridge length, and set my bullet seating die so that it seats the bullets .010" deeper, which would set them .010" off the lands. Before loading any ammo at this length I then test to see if the round will fit in the magazine, some haven't and I seat bullets as long as I can that will fit the mag. BTW, all this info is useless when loading mono-metal bullets such as the Barnes because they don't do well seated anywhere near the rifling, from what I have read.

1. I measured 24 of the 250 gr Partitions. 1.264.9" +/- 0.004". So that doesn't explain the issue since I was seating 0.023" off of the measured lands OAL.

2. I'm well above crimping the brass, in fact that was the first thing I did - checked that and measured the neck diameter. And as I seated the bullets deeper, things were fine.

3. Also, when I "forced" the bolt closed and chamber a round, I had to hammer open the bolt (with my plastic bullet remover hammer) to extract the cartridge. And it pulled the bullet forward about .040". So that tells me the bullet jammed into the lands.

4. I confirmed all of my brass is .005" or more below max length.

I have not tried this with any resized brass.

Very strange.

Maybe there were 3 odd sized bullets or something in the box that I loaded. I doubt it, but I will try another bullet and measure it first. I guess I could also pull the three loaded rounds and measure those bullets as well and see if they match the measurements above.

quote:

Originally posted by Luckyducker:
I have only load cup and core bullets, and use an unsized fired case to set my seating depth. I hand crimp the neck slightly by pressing into the bench or other handy hard surface to the extent a bullet can be pushed into the neck with enough tension that it doesn't move easily. Then hand push a bullet that I will be loading into said crimped case neck, and then carefully chamber this dummy round into full lockup in the rifle that will shoot these rounds. Then I carefully extract the dummy and measure overall cartridge length, and set my bullet seating die so that it seats the bullets .010" deeper, which would set them .010" off the lands. Before loading any ammo at this length I then test to see if the round will fit in the magazine, some haven't and I seat bullets as long as I can that will fit the mag. BTW, all this info is useless when loading mono-metal bullets such as the Barnes because they don't do well seated anywhere near the rifling, from what I have read.

I had to read that twice since I'm not the sharpest tool in the shed.
YES, that works for figuring out the OACL for your gun. I did that for years and it works really just as well as the modified Hornady case thingy.
He claims that he knows what the OACL should be because he used the tool but maybe he should try your method too to make sure.
Yes, it works with mono metal bullets like barnes and then seat 35 to 50 thousandths deeper than MAX oacl in the rifle....because you're correct, they seem to shoot better with a bit of jump.

Zeke

...on the other hand, Hammer Bullets (also mono metal) seem to work best, for me, at about 20 thousandths off the lands

I don't use no stinkin tool to measure OAL: I do what LD said.
Your chamber is the tool.

quote:

Originally posted by dpcd:
I don't use no stinkin tool to measure OAL: I do what LD said.
Your chamber is the tool.

Technically the chamber is what you're trying to measure and the case / bullet is the tool. (insert smiley face here, if you want)

Having done it that way for 40 years and now using the tool for 10, it's easier for ME to get a correct reading even if the bullet sticks in the lands.
The bullet can pull slightly back out of the case, with the old method, and give a false reading so do it several time with this method to make sure.

Zeke

quote:

Originally posted by ZekeShikar:

quote:

Originally posted by dpcd:
I don't use no stinkin tool to measure OAL: I do what LD said.
Your chamber is the tool.

Technically the chamber is what you're trying to measure and the case / bullet is the tool. (insert smiley face here, if you want)

Having done it that way for 40 years and now using the tool for 10, it's easier for ME to get a correct reading even if the bullet sticks in the lands.
The bullet can pull slightly back out of the case, with the old method, and give a false reading so do it several time with this method to make sure.

Zeke

I progressively increased the seating depth by .005" until the bolt would close (I never forced it like the one test I did and purposely forced close).

I loaded up some extra Sierra GKs one time as sighting bullets in 280 AI load development. Didn't measure them since they weren't on the load development list and used the Sierra seating depth recommendation. Damned it if wasn't too long, but that wasn't a mismeasurement issue, it was an issue of not measuring and trusting the reloading data from Sierra!

their job is to give you their results for a safe load using their equipment.
your job is to use that information to make safe loads for your gun.

if you have to seat the bullet a butt ton deeper then you should adjust your data, move on to another bullet.

I would have already done a pound slug of my rifle and had the measurements in hand [shrug] but that's how I do things.

I am sure someone said it, OAL can change for changes in ogive... that is, when the bullet finally meets max diameter ...

USUALLY setting at factory OAL will work.

Just have to say this; "pounding slugs" into your throat is not the best way to get that piece of data. That actually tells you nothing about the relationship of your bullet ogive and your throat interface. Maybe if you used an optical comparator. But that is just me; everyone else drive on.

I use the same method that LD explained. Just guessing that you are not measuring correctly. If you have other bullets that load just fine but other bullets won't then either the ogive is different between the two or you are measuring wrong. Just a guess though.

Please correct me if I’m wrong/making a wrong assumption...

The hornady tool is essentially a modified case and the ability to measure where the bullet contacts the lands is what you measure with it.

You seem to be stating that you measured the length with contact to the lands with a cup and core bullet, and loaded your partitions to the same length? If so, you are not using the system correctly.

Did you try using the hornady tool to measure with the partition bullets that are not working when you loaded them?

The tool is designed to find the length to the lands of any particular bullet. I have had issues with different lot numbers of Partitions not having the exact same ogive, and turning a repeatable .5MOA load to a 1” load based off of COAL.

You need to measure with each lot of bullets with the LAL comparator and then adjust, all bullets are a little different, and the change can be not visible to the naked eye but substantial.

The bullet’s overall length doesn’t matter- where the bullet makes contact with the rifling does for shooting safety... cartridge OAL matters for feeding from the magazine.

If you are measuring COAL with an exposed lead bullet, often there can be some variation based on the bullet nose being battered in the box and thus inconsistent. Using a comparator insert for OAL removes that variability. Since most seating dies contact the bullet on its ogive somewhere, usually the seating dies do a better job than most think as far as consistency.

The bullet’s profile can also affect feeding, but usually that is secondary to safety. Loading long as safe usually helps accuracy. Using the listed OAL in the manual should give optimal feeding.

Use the "rod method" for measuring COAL.

Could it be possible that those bullets are .366 and not .358?

The only cause I can think of for this problem is if the measuring insert (the ring which touches the bullet ogive during measuring) is of a different inside diameter than the land diameter of your barrel.

To check that, you would need to slug the barrel, and compare the diameters. It can't be measured directly if your rifle has an uneven number of lands and grooves, but easily solved with some maths of course.

Two fool proof methods we use are.

1. SLIGHTLY size the mouth of a case, put a bullet seated way out and chamber it.

The chambering action will seat the bullet into the case, which will give you the MAXIMUM length you can seat that bullet.

2. Put a bullet in the chamber, while the rifle is on a rest, hold the bullet in with something - I use a screw driver!

Put a cleaning rod in from the muzzle, push until it touches the bullet.

Measure the length.

Remove the bullet, close the bolt, and measure again.

The difference in lengths is what you loaded round maximum length could be.

This never fails, and can be used with any bullet, in any rifle, in any caliber.

People bring all sorts of gadgets for this, I never use them.

quote:

Originally posted by Saeed:
Two fool proof methods we use are.

1. SLIGHTLY size the mouth of a case, put a bullet seated way out and chamber it.

The chambering action will seat the bullet into the case, which will give you the MAXIMUM length you can seat that bullet.

2. Put a bullet in the chamber, while the rifle is on a rest, hold the bullet in with something - I use a screw driver!

Put a cleaning rod in from the muzzle, push until it touches the bullet.

Measure the length.

Remove the bullet, close the bolt, and measure again.

The difference in lengths is what you loaded round maximum length could be.

This never fails, and can be used with any bullet, in any rifle, in any caliber.

People bring all sorts of gadgets for this, I never use them.

Thanks! I used to use the first method years ago before I get the Hornady tools!

I do not crimp bottle neck cases, I go for all the bullet hold I can get. The seating die does not have case body support.

If for some reason I do crimp the neck of a bottle neck case I never get carried away. When the neck of the case digs into the bullet while the bullet is being seated the shoulder/case body junctures increases in diameter. The increase in diameter forces the shooter to size the case when the bolt is closed.

F. Guffey

some if not all Nosler have a double radius, I read about this some moons ago and it was the answer to your problem..smaller front end diameter than the straight rear portion..Might get a better explanation from Nosler with a telephone call...

to check AOL I use a wood dowl, length of welding rod, or gun cleaning rod. stick a bullet (bullet only) snugly in the lands with the dowl, then go to the muzzle and push the dowl to the bullet, mark the dowl at the muzzle with pen or whatever, take the bullet out of the lands an repeat to the bolt face.mark the dowl and measure the two marks with mic and you have the OAL with that particular bullet. You have to repeat this operation with bullets of different makes and weights or any change..works extremely well and inexpensive I might add.

I never crimp any loads except rimmed cases for pistols, double rifles and lever guns in some cases.

I solved the mystery. I was out a few days hog and aoudad hunting.

Got back tonight and went through everything again - all bullets, all measuring techniques (those mentioned by folks in the thread and more) - consistent result - all methods yield 0.048" shorter than the Hornady tool. So it had to be the gauge case I was using on the tool and it wasn't seating as deep as a standard case (I even measured the seating depth delta between the gauge case and other cases and got .048")

Hornady does not make a 358 Norma gauge case, so I ordered the proper tap and made one 2 years ago. For whatever reason, when I was drilling out the hole, I got some scoring circumference wise on the case. It was a fired case, but the other fired cases I used didn't have an issue seating, so it had to be the scoring. I don't have a lathe so I figured my Willis collet die would fix it up. SURE NUFF! Ran measurements with the gauge case - matched all of the other measurements.

Of course, now I'm think do I seat the bullets deeper or lengthen my throat (which I did in my 35W and 404J for specific bullets I shoot).

I'll start with the standard spec throat and see what I can do.

I feel like that internet meme where Batman is slapping Robin - and I'm Robin

I also use the LD method. Even if the bullet catches a little and pulls out of the case, it leaves a scratch on the bullet. Just push the bullet into the case to the scratch and presto, your length.