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Plunk test

5K views 36 replies 12 participants last post by  Gahunter12 
#1 ·
My dummy round failed, what should I look at, OAL or flaring?

Using 45acp LRN, OAL is 1.250, case(neck) flare is .471

She sticks in barrel and is about .062 outside from flush with barrel.

I should just go in more with bullet, do you think I have an issue with flare?

Let me know if you need more info
 
#2 · (Edited)
I would measure the chamber to the back of the hood with inside caliper. them I would put the barrel in the slide with a the loaded round and push the barrel all the way to te rear and the bullet forward and check the clearance. If you stick the loaded round under the extractor first and slip the barrel in it is easier to do.PS:Idid not see the .062 number you probably have a unfinished chamber that needs finish reamed.Was it .0062?
 
#3 ·
Many cast 230 gr RN bullets have a very pronounced shoulder and a short nose. It is quite possible that the bullet is hitting the rifking and stopping there. If the bullet you are using hase the shoulder you may need to seat deeper. When I load RN with the shoulder I do it the same way that I do SWCs. Measure the length to the shoulder, it should be about .935". Any longer and that should will many times hit the rifling.
 
#4 ·
When using the .471 crimp that you have now, is it eeeeasy to press on the case head until the cartridge sits flush with the barrel hood, or do you feel a some pretty good resistance when you do that?

If it is really easy to push the cartridge flush, I'd say drop the crimp back to .469 and see how the round "plunks" for you.

If you're feeling some real resistance, I'd try seating the bullet .005" or so deeper and see how it plunks.
 
#7 ·
I agree with Alland. My crimps are at .471-.472". With lead RN I have to set my OAL to 1.240. My plates RN bullets seat at 1.260". I tried seating my lead bullets at 1.250 and had the same problem.
 
#8 ·
The easiest way to tell if the problem is the crimp is to reduce the crimp to 0.469" or 0.470", if the round still does not pass the plunk test you will need to shorten your OAL. 0.471" should be in the ballpark so I'm betting the problem is either your OAL or shaved lead.

Are you seating and crimping in the same step? I ran off a lot of 400 rounds (225gr LRN) and had the same problem as you are experiencing. The die must be ajusted almost perfectly and probelms with cast bullets can still happen. If the die is not ajusted correctly the die will start to crimp the case while the bullet is still being pushed into it. A slight roll of lead forms at the case mouth and prevents the round from chambering correctly. The answer to this problem is to seat without crimping in the first step then crimping in a seperate step.
 
#9 ·
No I can not force it flush to the barrel, if I did I may not get it out unless I use some pry tool, my fingers would not get it out.

I'm using lee carbine dies, and I'm seating in one die and using a LCD die for crimping

I'll check the Shoulder
 
#11 ·
Ok well I'm out here now, I'll be adjusting and let ya guys know when I pass
 
#12 ·
TW45 - take a colored marker and paint the nose of your bullet. Insert it into the chamber and tap it with your hand. Then remove it from the chamber by tapping it out from the muzzle end using a wood dowel or some other non metallic instrument, even if it's a screwdriver that''s been taped over to cover the metal. If the colored markings are scratched, your seating length is too long for those bullets. Run them through your seating die in small increments until they seat flush with your hood. Horoscope Fish asked about this, but we didn't hear a response. Sorry, can't type fast enough!

In my opinion, your crimp is fine, it's the COL for your particular chamber that needs to be addressed.
 
#14 ·
I have it flush to .010 under at a OAL of 1.216

But it still seems it sticks in the barrel, I can hold the barrel up side down and the cartridge will not fall out freely, I give it some firm jiggle and the the cartridge will fall out. Normal?
 
#17 · (Edited)
This is what's working, AOL 1.206 with a crimp at .469

She plunks in freely and falls out freely, what you think of the numbers, a bit small on AOL?

Sorry it's a 230gr LRN
 
#18 ·
This is what's working, AOL 1.206 with a crimp at .469
That's a pretty short OAL for a 230 grain LRN in my experience, but it could be the bullet you're using... And it *is* passing plunk testing, so chances are it's fine.

That being said, what bullet, exactly, ARE you using?
 
#19 ·
there are many factors to consider for a good plunk test. as always, the acid plunk test must be accomplished in the chamber/barrel of your gun, and nowhere else. factors that can make for a bad plunk test are - the crimp diameter, oal, bullet shape, case length (for rounds that head space on the case mouth).

if a load recipe calls for a particular bullet type/shape, which dictates a specific oal, and you build a dummy round that fails the plunk test in your gun's chamber (too proud of the hood, sticks, etc.) and you reseat the bullet a tad deeper and it shortens the oal, you are not building to the load recipe and an unsafe round may be the result ...

is your bullet the precise same as dictated by the load data and you are not substituting a different brand, type, shape? is the case length to spex or under spec'd? is the crimp correct and matches or is under the load data recipe? is your barrel's chamber clean?

when i load 230gr missouri lrn for my rem 1911r1, i use an oal of 1.245" for a perfect plunk test.

most 1911's feed well with lrn's, but the shape of lswc's will be easier to plunk test (and hopefully they will feed well in yer 1911) ...

the lswc plunk test
 
#25 ·
I test fired 4 rounds at 5grns

cartridge measure .473/.475

with a shorter OAL than normal I posted pics of the primers also, see what anyone thinks? to much pressure for a 1.206 OAL 45acp?


 
#29 ·
FCD- factory crimp die. Shellplate is the plate that your case sets in while loading on a progressive.

One thing I learned with lead while doing plunk tests is the lube can build up in the camber while doing a plunk test causing them to stick enough not to fall freely. I had that happen to me. I chased my tail for 10 min trying to figure out why my loads started sticking. Now I pick about 10 random loads out and clean them off with alcohol pad to remove excess lube build up around the case mouth before plunk testing.
 
#31 ·
Ah,! I should have known that, lol

Yea I agree on the sticky, I believe some of that was happening.

Im concerned of how short I needed to go on the OAL just to get it flushed. I posted some pics of the primers on 1st page for a opinion of the said shot cartridge.
 
#30 · (Edited)
Sometimes we overthink the issues. Spend 10 min and try changing the oal in increments. Just make a roud with no primer and no powder. Seat a bullet at your present setting, plunk. if fail, seat a little deeper, plunk, repeat until you pass. once pass measure oal. if not pass, the issue is not OAL.

Someone may want to chime in with an OAL to not go shorter than safely.
 
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