How many dummy rounds

[AJC1]

When building dummy rounds for testing function how many do you build and how do you use them. Do you make 3 exactly the same length, see if they work and then go shorter? Do you build a stack in size decreasing by .003 or .005 and start with the shortest and cycle them through till you get a problem and go with the previous length that cycled well. Interested. I'm asking for a lever gun but any semi would also be tested and if your tests are different by gun type, I'd like to know how and why.

 

[ballman6711]

For me it's usually just one, but can be as many as three or four.

The way I do it is to adjust my die for my desired seating depth, then lock it down. If my COAL is where I want it (or maybe .002~.003 +/-) then I'm done and move on to my crimp die (if it's a caliber that I crimp). A small crimp, then plunk test, adjust as needed, repeat, and finally lock that die. My last step (for a semi) is a function test. I load my round into the magazine and chamber it by hitting the slide lock. I will do this several times, and measure for setback after each chambering.

I use LNL bushings in a Horndady SS press, so once my dies are set they stay that way unless I change to a different bullet. My COAL variation on my finished rounds is generally .003 at most, and usually .002 or less.

chris

 

[LiveLife]

When building dummy rounds for testing function how many do you build and how do you use them. Do you make 3 exactly the same length, see if they work and then go shorter? Do you build a stack in size decreasing by .003 or .005

I'm asking for a lever gun but any semi would also be tested and if your tests are different by gun type, I'd like to know how and why.

For semi-auto pistol cartridges that headspace off case mouth, how many dummy rounds I make depends on resized case length variance and bullet setback:

• When using mixed range brass, I will measure resized length of several samples of each headstamp brass (I have found variation in length could vary by more than several thousandths)

• For determining Max OAL using the barrel, I will use shorter length cases to make dummy rounds that will allow more bullet nose to extend above the case mouth before bullet nose/ogive contacts the start of rifling.

• Once Max OAL is determined with shorter cases, additional dummy rounds with longer cases will allow the bullet nose/ogive to move back away from the start of rifling by few thousands when case mouth headspaces on the chamber and shorter length cases will headspace off extractor which also moves bullet nose/ogive back away from the start of rifling. (For 40S&W, Max OAL can be longer than SAAMI max length of 1.135" and depending on factory/aftermarket barrel, upwards around 1.180"-1.200")

• For determining Working OAL, I will use the dummy rounds I used to determine the Max OAL (With different amount of bullet nose/ogive sticking above the case mouth) and feed them from the magazine without riding the slide. If Max OAL dummy rounds reliably feed and chamber from the magazine without bullet setback, I will not make additional dummy rounds and move onto powder work up using the Working OAL.

• If Max OAL does not reliably feed from the magazine (whether shorter/longer case dummy round or both), I will incrementally shorten the OAL by .005" until they do.

• If I experience bullet setback with particular headstamp brass, I will make additional dummy rounds with thicker case wall brass to minimize/eliminate bullet setback or consider using larger diameter bullets if loading 9mm (.3555"/.356" vs .354"/.355") - https://www.thehighroad.org/index.php?threads/9mm-pressure-signs.892618/page-2#post-12011358

• And if you are pursuing greater accuracy and not at max charge, I would try incrementally decreasing the OAL to see if group size decreases. It it does, I use shorter OAL. (Think deeper seating depth increases neck tension)

If you are getting significant swings in OAL and reloading on progressive press, it could be shell plate tilt/deflection issue and try pre-resized brass - https://www.thehighroad.org/index.p...progressive-press.833604/page-2#post-10779806

Depending on the consistency of bullet nose/ogive, OAL variance around .005" is typical and more consistent bullets will produce less OAL variance (I get .002"-.003" with RMR jacketed bullets using mixed range brass and .001" with pre-resized brass once shell plate tilt/deflection factor is removed). And if bullet tilts during seating and/or case neck collapses a bit, these will stack on top of OAL variance.

 

[mdi]

I start off with an OAL recommended by the bullet/mold manufacturer, assemble a dummie and plunk test. If needed, I'll adjust seating depth. When I determine a good OAL, I'll keep a dummie with my die set, one for each bullet I use (I keep my dies in "tupperware" sandwich boxes. I use a Co-Ax so dies are "loose" in the box with extra examples of bullets and dummies)...

 

[Mark_Mark]

I do a full mag worth of dummy, measure before and after. Make sure my crimp is good after 3-5 full cycles

like yesterday, I did 12 .357 @1.590. It didn’t feed good, (and tossing loaded dummy rounds straight to my forehead, got old fast), So I drop down to @1.575 and it was smooth like ice! and I put on safety glasses too

 

[GeoDudeFlorida]

When building dummy rounds for testing function how many do you build and how do you use them. Do you make 3 exactly the same length, see if they work and then go shorter? Do you build a stack in size decreasing by .003 or .005 and start with the shortest and cycle them through till you get a problem and go with the previous length that cycled well. Interested. I'm asking for a lever gun but any semi would also be tested and if your tests are different by gun type, I'd like to know how and why.

Just one. So I can do a quick reset on the seating die to make that round again.

I use the chamber and a bullet to measure and then calculate maximum COAL, then back-calculate to a reasonable/preferred case fill which lets me be under that max finished length number, over the minimum powder fill space, still fit a magazine/loading ramp, and not interfere with any lifters or action parts. Typically the first one fits and works so I fill the primer pocket with silicon sealing gel and leave it be. They make good APD's.

After I finally broke down and bought a case gauge I checked all of my old test dummies/setup rounds and they all passed. Knew they would.

 

[AJC1]

I do a full mag worth of dummy, measure before and after. Make sure my crimp is good after 3-5 full cycles

like yesterday, I did 12 .357 @1.590. It didn’t feed good, (and tossing loaded dummy rounds straight to my forehead, got old fast), So I drop down to @1.575 and it was smooth like ice! and I put on safety glasses too

Did you do incremental testing or just jump .015 in one shot. My 357 seating die is currently locked a 1.585. I may have to change when I get and test the rifle.

 

[Airborne Falcon]

Great thread! Watched and subscribed.

 

[Mark_Mark]

Did you do incremental testing or just jump .015 in one shot. My 357 seating die is currently locked a 1.585. I may have to change when I get and test the rifle.

just jumped down .015, my tolerance is .005 so 1.575 sounds right

 

[AK Hunter]

I make up a mag full just the way they come out of my press (from long to short) so I know anything I make on my press will cycle through my guns. I fill the primer holes with a thick plastic glue called Shoe Goo, I also drill a hole through the brass case so I don't get dummy rounds & live rounds mixed up.

 

[AJC1]

just jumped down .015, my tolerance is .005 so 1.575 sounds right

Try a rnfp bullet and a swc stem. You should be able to cut that in half pretty easy. My tollerance is normally 1.585-.002. Even with mixed cases I can normally hold that.

 

[Mark_Mark]

Try a rnfp bullet and a swc stem. You should be able to cut that in half pretty easy. My tollerance is normally 1.585-.002. Even with mixed cases I can normally hold that.

that’s the stem with the flat? I think I have a 9mm one I can try

 

[film495]

I make several, and put at least one aside to use as a reference for future use. Then just some amount, 5 or 10 that match exactly what I think I'll be loading, after any other tests, and load them into a magazine, and cycle them several times and see if they cycle correctly, and then measure them again for OAL to see if the bullet is staying put.

 

[Mark_Mark]

I got so many rounds that I need to pull. Got the RCBS puller and 9mm and .40 collet, now I need .45 collet

 

[AJC1]

I got so many rounds that I need to pull. Got the RCBS puller and 9mm and .40 collet, now I need .45 collet

Yes the swc or wadcutter stem is mostly flat. I spent an hour or so on the back of a kemitic hammer taking my dads 357 rounds appart. He loaded with ramshot competion, and the cases are sticky after firing. First 50 disassembled sized and now I am trying to decide unique or 2400.

 

[cfullgraf]

One dummy round if that.

I do not load many loaded rounds until I shoot them for function.

 

[Rule3]

I dummy round for each bullet I use and for every caliber. I just use them to set up dies as I change around a lot. Mostly handgun, several for rifle.

If it fits it shoots!

 

[edwardware]

When building dummy rounds for testing function how many do you build. . .

I suppose it depends on what function issue you're diagnosing. I usually don't make dummy rounds; a close examination of the gun will reveal a maximum that will feed and eject (magazine, action/lifter/throat/plunk, etc). I load near the max length, go shoot, and make notes on function.

 

[lordpaxman]

I never used to make dummy rounds, just split necks for measuring max COL. Now I make a dummy round for press setup only. I use live rounds for any function test. Good luck.

 

[Mark_Mark]

I never used to make dummy rounds, just split necks for measuring max COL. Now I make a dummy round for press setup only. I use live rounds for any function test. Good luck.

the old neck split trick! I use to do that, still will for rifles

 

[bluejay75]

One for each type of bullet that I load then crimp the pist out of it to make sure it doesn’t move when I’m setting up my dies. Very important and accurate with flat seating stems and flat nose bullets.

 

[Mark_Mark]

One for each type of bullet that I load then crimp the pist out of it to make sure it doesn’t move when I’m setting up my dies. Very important and accurate with flat seating stems and flat nose bullets.

I need to look tonight to see if I got some flats!

 

[AJC1]

One for each type of bullet that I load then crimp the pist out of it to make sure it doesn’t move when I’m setting up my dies. Very important and accurate with flat seating stems and flat nose bullets.

I have dies that dont get changed until I run out of a bullet. Bullets that I cast are locked down. Cheaper than owning multiple presses or dillon's by a lot.

 

[bluejay75]

I need to look tonight to see if I got some flats!

If its a Lee Mold you can try to make a flat by grinding. I have botched that operation multiple times but you may be more mechanically inclined than I am. Lately I have found that the Hornady dies come with a flat seating stem. A good flat seating stem will seat most anything in pistol.

 

[Mark_Mark]

If its a Lee Mold you can try to make a flat by grinding. I have botched that operation multiple times but you may be more mechanically inclined than I am. Lately I have found that the Hornady dies come with a flat seating stem. A good flat seating stem will seat most anything in pistol.

I could do it 1 minute with a lathe… if I still remember how to center on a chuck.