Modified cases for Hornady Lock-N-Load gauge

[Buckys]

Read through some of the posts on using the 280REM case for finding the distance to the lands in my 280AI (SAAMI/Kimber Montana) chamber.

I plan to stay at 50thous from the lands.

Seems like the 280REM should be adequate for this case?

I assume that most folks who are using brass fired once or more in their chambers without resizing are looking for maximum precision, possibly to run closer to the lands than I am intending to do here?

Thanks for the help.

 

[Carlos88]

Changing the OAL can make dramatic improvements. Start at .050, then 0.40, etc.

What bullets are you planning on using?

The .280 Rem should work.

 

[Buckys]

Carlos, I plan to start with the 140AB, 140TSX and 140TTSX. My Montana likes factory 140AB and also like my RE22 loads with 140TSX ~0.4-0.5 MOA. 162 ELDX and 160AB were ~1MOA.

I want to check my jump on what has worked well and stick with that starting point. I'd prefer to start 0.050-0.080 off the lands.

From there, I will start playing with my 150's - AB, Ballistic Tips, TSX and Scirocco-II - and the 154 SST, and then come back to 160 AB, Fusion and Partition and 168 Berger Classic Hunters.

 

[Carlos88]

Sounds like a plan. I'm still working on my .280AI (Kimber). Started with 140TTSX and searching for some 140TSXs. Accubonds if I can find some.

 

[Pdyson]

Make one from one of your older fired cases. Amazon sells the tap and proper size drill for $19. That drill bit is an odd size that does not come with most drill bit sets. So mark it or keep it separate. I found my tap but can't find my drill bit.

HSS 5/16-36 Right hand Thread Tap and 7.3mm Drill bit Amazon product ASIN B08FFDJ867

 

[AZShooter]

Those lock and load cases use a non standard thread. The tap and tap drill can be purchased on line. I helped a friend figure out what the thread was but it has been years and I forgot. The case must be held in a lathe then drilled and the tap started square in the hole. Without the proper equipment it will be imprecise.

You really don't need to bother. Create a dummy round. Seat a bullet long in a case. Polish the jacket with fine steel wool. Try to close bolt. It may or may not close depending how much of the bullet is engaging the lands. If difficult then seat deeper and try again. At some point the bolt will close with mild resistance. The lands will engrave the jacket of the bullet. The equally spaced marks should be easy to see. Polish the jacket with each attempt. As you seat the bullet deeper the long rectangular marks will begin to get shorter, become square then the rectangle turns sideways. At this point you are getting close to where the bullet's ogive is just kissing the lands. Very faint marks will be seen. At this point the bullet is at zero. Keep that dummy round as a reference. At this point, you either need a calibrated seater die like a Redding competition seater or a comparator so you can measure the distance you moved the bullet deeper in the case.

If you don't have any of the things mentioned above and have a plain seater die the seater stem you can still get darn close to what you want with no measurement tools. A seater stem has a certain number of threads per inch. Some RCBS dies use 28 TPI. If you divide 1 by 28 you get .0357" per full rotation of stem. This can give you an approximate value. 1.4 turns would give you your .050 jump to lands.

I am willing to bet there are many handloaders here that did not have much in the way of measurement equipment when they started out. A hunting rifle doesn't need much to have it function. All that is required is to seat the bullet to fit and feed from the magazine, and make sure it doesn't touch the lands. Then the powder charges are worked up. All this without measuring anything! In fact, I still start the loading process that way. If I am not getting the accuracy I want then I will tweak the seating depth in .003" increments trying for a tighter group. Naturally this means seating the bullet deeper as it won't fit magazine going the other way.

Hope this helps.

 

[Buckys]

Make one from one of your older fired cases. Amazon sells the tap and proper size drill for $19. That drill bit is an odd size that does not come with most drill bit sets. So mark it or keep it separate. I found my tap but can't find my drill bit.

HSS 5/16-36 Right hand Thread Tap and 7.3mm Drill bit Amazon product ASIN B08FFDJ867

Thanks. I've considered sending off a few shot cases to do this ... I know I'd end up drilling it on an angle if I DIY it.

 

[Buckys]

Those lock and load cases use a non standard thread. The tap and tap drill can be purchased on line. I helped a friend figure out what the thread was but it has been years and I forgot. The case must be held in a lathe then drilled and the tap started square in the hole. Without the proper equipment it will be imprecise.

You really don't need to bother. Create a dummy round. Seat a bullet long in a case. Polish the jacket with fine steel wool. Try to close bolt. It may or may not close depending how much of the bullet is engaging the lands. If difficult then seat deeper and try again. At some point the bolt will close with mild resistance. The lands will engrave the jacket of the bullet. The equally spaced marks should be easy to see. Polish the jacket with each attempt. As you seat the bullet deeper the long rectangular marks will begin to get shorter, become square then the rectangle turns sideways. At this point you are getting close to where the bullet's ogive is just kissing the lands. Very faint marks will be seen. At this point the bullet is at zero. Keep that dummy round as a reference. At this point, you either need a calibrated seater die like a Redding competition seater or a comparator so you can measure the distance you moved the bullet deeper in the case.

If you don't have any of the things mentioned above and have a plain seater die the seater stem you can still get darn close to what you want with no measurement tools. A seater stem has a certain number of threads per inch. Some RCBS dies use 28 TPI. If you divide 1 by 28 you get .0357" per full rotation of stem. This can give you an approximate value. 1.4 turns would give you your .050 jump to lands.

I am willing to bet there are many handloaders here that did not have much in the way of measurement equipment when they started out. A hunting rifle doesn't need much to have it function. All that is required is to seat the bullet to fit and feed from the magazine, and make sure it doesn't touch the lands. Then the powder charges are worked up. All this without measuring anything! In fact, I still start the loading process that way. If I am not getting the accuracy I want then I will tweak the seating depth in .003" increments trying for a tighter group. Naturally this means seating the bullet deeper as it won't fit magazine going the other way.

Hope this helps.

Yeah, no lathe = I'll mess it up. I've tried similar methods to the alternate method that you describe ... I've just grown impatient with that.

I've got the 300WM, 243 and 65CM mod cases for my LNL and laziness and lack of patience has motivated me to find more.

 

[bomberodevil]

Thanks. I've considered sending off a few shot cases to do this ... I know I'd end up drilling it on an angle if I DIY it.

I've hand-drilled abut 7-8 used brass cases and I've only ruined one. I've got a rubber vise shaft holder for golf clubs, and it holds the cartridge in place while drilling at slow speed and hand tapping. It can be done by hand.

Amazon product ASIN B00SA5JBZW

 

[Sockeye66]

I've drilled and tapped case and it does work, but now I have dummy cases for each cartridge that are deprimed and sized then a small slice is filed vertically down the neck with the side of a jewelers file to the shoulder junction, insert bullet long and chamber. I'll do this a few times to get a solid reading. If the neck gets to loose after multiple uses, just resize.

 

[QuietTexan]

I assume that most folks who are using brass fired once or more in their chambers without resizing are looking for maximum precision, possibly to run closer to the lands than I am intending to do here?

Anal- retentive level - get Unknown Munitions to make one from your own fireformed brass.

Modified Case - Unknown Munitions

A modified case made from any brass we have here in the shop. Each modified case purchase will come with your choice of in stock bullet. If your cartridge has a standard bolt face (+/- .470), it is Standard fee. If your cartridge has a magnum bolt face (+/- .540), it is a Magnum fee.…

www.unknownmunitions.com

Hard to find stuff/ New chamber/ Something I don't have brass for - buy a COAL case from Unknown Munitions, even though it's not formed
Easy to find stuff - Get a Hornady Case
DIY - Drill out a case that you have
Also DIY - Cut a slit in the case neck

Using the tool:

Maximum attention to detail - run a headspace comparator on the COAL case and a fully formed case. Account for that difference in BTO. COAL Case - BTO 2.940, Shoulder 1.750. Resized, Shoulder 1.755. Add 0.005" to the BTO, use 2.945" to account for the gap between the case head and bolt face that fully formed brass won't have, which comes from shoving the undersized COAL case forward into the shoulders of the chamber.

Functional method - Call the headspace difference in formed and unformed shoulders NBD, move on with life because the difference in being 0.005" and 0.010" off the lands doesn't matter a hoot, start back at 0.020" off so you don't stick a bullet in the bore and miss a shot. Hunting gun, bench gun, comp gun, doesn't matter what kind of gun, IMO if you have to be within the first hundredth off the lands I don't want to shoot it and I'll go looking for a deeper node.


Here's the real kicker - it doesn't matter at all. As long as you work up your powder charge and as long as the bolt closes, does seating depth as a measurement matter? Not for anything other than repeatability. The only point of "finding the lands" is to find the longest you'd load to. The "distance to lands" measurement ceases to have any relevance once you pick your starting point. So don't get hung up on wanting to be a certain distance off, work on being where the thing shoots good. The measurements help quantify testing and structure the process so you don't waste components finding a good depth, the 0.020" off rubric is a common starting point, but there's nothing about any measurement that makes it better or worse than another.


As long as you don't accidentally jam a bullet by not paying attention, other methods that work just as good for a starting point: use book COL from the bullet manufacturer, use the BTO of a factory loaded round, or use where the base of the bullet seats at the shoulder, then you work longer.

 

[Buckys]

QT, thanks for that detail. I'm still absorbing but I appreciate the "anal retentive level" etc. breakdown. Trying to keep my OCD in check

 

[Ga6570]

i was going to offer to make you one as well - ive made a good number of them for myself and friends who have "non-standard "cartridges. i would have charged $15 for it. still happy to do it, but looks like QT's reply and unknownmunitions likely has a nice system setup for stuff like this. -

 

[Buckys]

Thanks. I appreciate the friendly offer. The good will of LRH members makes this place great.