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1,07 too tight for N320 and precision moly?


Frady

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Greetings all,

I have a couple boxes of Precision 147gr bullets and some N320 that I am trying to work up a load with and I am having trouble loading too short.

Armalite AR-24 (EAA Witness iteration with cut rifling)

VV N320

Precision 147gr

I have read (after ordering them of course) that some people have had issues with the profile of precision molys and I think this is my issue. My original starting load was 3.1gr N320 and 147 gr precision moly set at 1.15". This is not even close.

To get the bullet seated far enough not to hit the rifling I have had to work down to 1.07". Lyman list the minimum OAL for 147 lead to be 1.05, but they do not have N320 as one of the powders.

Considering N320 is a fast powder and I am so close to the minimum OAL what are your thoughts on this load? Thanks in advance.

Edited by Frady
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Start below the starting load and work up carefully.

Also, contact manufacturer/gun smith/bullet manufacturer and check if the barrel was actually chambered so short or if your reloading technique has a problem.

I don't see the precision 147gn bullets as having any difference in ogive from the 115 or 124gn bullets and I have no problem loading them long (but that is the chambers in my 9mm's and only one has a custom match barrel.

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The VV manual recommend 1.13-1.14. That is with a 3.1 grains of powder.

Why do you need it soooo short? By touching, how much touching.

VV is a fast powder, loading that short may cause you some real problems.

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Here is a picture of 4 cartridges. Apologies for the phone pics, but it's the best camera I have.

From left to right

1.05 -----> 1.12 -----> 1.15 ------> 1.15 Winchester white box 1.15

http://img40.imageshack.us/i/imag0075ra.jpg/

Here is the WWB in the barrel

http://img267.imageshack.us/i/105ql.jpg/

Here is the precision 147 loaded to 1.15 (same as WWB).

http://img717.imageshack.us/i/115dq.jpg/

1.12

http://img844.imageshack.us/i/112ep.jpg/

1.05

http://img842.imageshack.us/i/wwbk.jpg/

The WWB of course spins freely and does not touch the lands. The 1.05 does not either, but just barely. 1.06 will touch the lands.

What could I be doing to cause this?

Edited by Frady
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Have you double checked the diameter of the bullets? It sounds like they may be larger than they should be.

Brian

Yeah 1.05" COL is not the problem here. I've never heard of a 9mm load under 1.150" that won't chamber correctly unless the ogive of the bullet is almost square!!

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I have been doing some reading over at CZForum and it seems that a lot of people over there report seating at 1.09 max COL. I see several people reporting lower than that, though with 124 gr bullets.

My gun is an iteration (most of the dies are the same or close) of an EAA witness which is an iteration of a CZ.... so this could just be a chamber issue.

The bullet is the correct diameter, but I think the shoulder is what is making the difference. If you look at the pictures the ogive is different than WWB.

*edit*

I think I have found a thread describing exactly what I am experiencing.

https://www.thehighroad.org/showthread.php?t=421949

Short version: the CZ (and therefore my iteration of a cz iteration) is a short chambered design intended for traditional conical ogive. Those bullets with wide ogives (great pictures in that link) such as precision will not work well in a CZ chamber without very deep seating.

Unless I have completely misread this (and PLEASE tell me if I have) I will need to order some different bullets. Perhaps some traditional ogive bullets from someone like MG. *sigh*, so much for saving money eh.

* another edit* Some really good reading in case anyone else comes across this issue...

http://www.czforumsite.info/index.php?topic=36061.0

http://www.czforumsite.info/index.php?topic=36039.msg201459#msg201459

Edited by Frady
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