OAL on campro 9mm RNHP

mctrigger

mctrigger

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Southern Alberta.
Here's the scoop. I'm new to reloading and need some advice on what's going on with a few failures of my plunk test.

The specs
Cz shadow 2
Using fired Winchester brass. Not sized for length
124gn campro rnhp
.5 grns below max charge.

The issue
So I cleaned my cz removed the barrel and she's pristine
Brass is clean and full sized, crimp is spec as per load data
Made a few dummy rounds to find my max oal. From the 5 dummies I made 1.115 was the length that 4 out of 5 was was making contact with rifling the 5th was around 1.17. So I knocked .015 off and loaded to 1.100.
Campro load data says OAL is 1.090 am I right to think 1.090 is the shortest I can load? If so my 1.100 should be fine I did 10 rounds first. shot them and was very nice. So I did 50 more. I plunk tested them all and found that 11 failed. I remesured and they came in at 1.100-1.97. Did the marker on the bullet and found that the campros had made contact with rifling. My crimp is spec and no case bulge. I took them down to 1.095 and they all passed there.

The question
1.090 OAL in load data is min right?
Is it common to see this variance in bullets? Or am I doing something wrong? By Variance I mean where the taper starts to turn to bearing surface.

Note my calipers work fine and hold zero.

Thanks. I hope this makes
Sense
 
never mind didn't read it all. IS it a new gun sounds like something is wrong with the barrel. I set my cam pro loads to 1.160 for my shadow and they run fine.
 
mctrigger said:
Not sized for length
So I did 50 more. I plunk tested them all and found that 11 failed.
Click to expand...

They may have failed because the case is hitting not the bullet: those cases could be beyond your chamber's measurements. It is hard to know without testing.

I run 45ACP 230gr TCHP (trunicated cone hollow point) and the case measurement and seating is very fussy for them. Campro COL is 1.180" and I am running them at 1.195" with cases between 0.890 and .893 as over that and they fail the plunk test.
 
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Aniest said:
They may have failed because the case is hitting not the bullet: those cases could be beyond your chamber's measurements. It is hard to know without testing.
Click to expand...

I should have said but when I plunk test it gets tight. I sharpied markered the bullets and roatated them I you can see they make contact at the transition of bearing surface to taper of the nose. Once I reduced the oal by .05 making them 1.095" they passed
 
Seems short, but the shape of the bullet is different than something like the Campro 124 RN. Therefore there is problems comparing one bullet to another because their dimensions differ. You should have lots of room to play depending on your powder. Something extra fluffy like Promo could be an issue but I doubt it. Make the cartridge fit the chamber.
 
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redruns said:
Seems short, but the shape of the bullet is different than something like the Campro 124 RN. Therefore there is problems comparing one bullet to another because their dimensions differ.

According to campro the col of the RN is 1.120 and the hp is 1.090. I am new to this and from
My googling, although lots of good info On oal I just want to confirm that 1.090 col is the shortest safe measurement. I don't have a way to test for runout but I suppose the bullet could be canted one way or another. It would be great if some one runs the exact setup and has the same issue or has seen it. Maybe I'm just too uptight. Haha.
Click to expand...
 
You have correctly found the correct OAL for that bullet in YOUR pistol. You are good to go. CZ have short throats.

So do Norinco.

Your ammo is safe, but you are closer to the max than you intended.
 
I keep reading CZ's have "short throats" but I haven't found that case. I can load 147 RNFP campros to 1.14 without issue, and the 124's to 1.16 without issue in my Shadow 2 (which I just sold) and my shadowline.

Without seeing it, I would guess that the case if flared or it's not sized properly. The 124 gr HP shouldn't be longer than a 147gr campro. 1.10 should most definitely work.
 
Ok great advice guys! Thanks for the input. Going to check case length on the next set of ones I do and take them
All to 1.095 should see zero failures there. I appreciate the input.
 
I don't see the issue that you are trying to bring. My understanding is that you are telling us that when you load too long they fail to plunk, and when you load with the suggested OAL they plunk.
Why dont you just load them to an oal that works, such as the suggested campro OAL?
 
I am using the same bullets with CFE Pistol powder. I am fairly new to reloading, but I have been setting mine to 1.090 as suggested by Campro and have not had an issue yet (300-400 rounds so far) with my HK VP9. Always feed, always fire. Not sure if they are effecting accuracy (I am hitting the paper), I am not that good of a shooter.

I have a feeling (and maybe more experience guys can chime in), but I think you only need to obsess with OAL for a specific firearms in rifle reloading for crazy accuracy. I would load them to the Campro spec and call it a day.
 
My cam pro at 1.09 are accurate. I have shot Zero HP bullets at 1.080. Also accurate. When loading short, cause your barrel says you have too, just go easy on the powder when you start working up your load. No biggie.
 
Kryogen said:
I don't see the issue that you are trying to bring. My understanding is that you are telling us that when you load too long they fail to plunk, and when you load with the suggested OAL they plunk.
Why dont you just load them to an oal that works, such as the suggested campro OAL?
Click to expand...

For sure but if 1.090 is the shortest I can go I figured if 1.100 worked it would be less pressure. But I suppose if I do what is in the data it's perfectly fine. I was also under
The impression the closer to the lands could make for better accuracy. But I think your opinion is spot on. I should just go to .090
 
I would redo your plunk, also you should be able to spin the round in the chamber. Then back up 0.015 again. I think most pistol bullets are not that accurate as far as base to ogive goes.
1.100 should be less pressure, but it's more pressure if you have one jammed in the lands because of a bullet variance or dirty die.
 
SoylentD said:
I keep reading CZ's have "short throats" but I haven't found that case.
Click to expand...

Right, so everyone else is just making $hit up? lol.

mctrigger said:
I was also under the impression the closer to the lands could make for better accuracy.
Click to expand...

OAL doesn't have the same affect (or as great an affect) in handguns as it does in rifles, especially since shots are usually taken within 25 yards. Find an OAL that works in all your handguns and stays above the safe minimum. I use 1.15 with 147gr CamPro's for my M&P, Glocks, and 9E but I run a batch at 1.09 for my brother because he has a PPQ, which like the CZ, has a short throat.
 
Shadows are reputed to have short chambers. I run mine at 1.100 and FWIW no feeding problems. Something else to consider with used brass is full length resizing doesn't get all the way down. Some guns with unsupported chambers will allow the brass to bulge just above the rim. Maybe so slight that it's not really noticeable by eye. When I get a batch of brass that looks a little sketchy, I'll sometimes run them through my resizer and check them with a chamber gauge before loading them.
 
I just looked at my load data, I had switched to 1.080"
CFE pistol powder 4.8 gr
Cam Pro JHP 124gr
FC brass
CCI primer
1/4 turn factory crimp die.
 
Shadows DO have short chambers, at least mine does.

I've used the Campro 124gr bullets, and the Berry's 124gr, and they both pass the plunk test at 1.087. I set the Bullet Barn 125gr LRN for 1.085.
 
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