300 Blackout Vectan powders and missing primers.

gilgsn

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Hello.
I just wanted to post my results reloading 300 AAC Blackout with Vectan powders. I was also surprised to see that a few of my extracted cases were missing the primer! I saw no signs of overpressure or unusual noise/recoil. The speeds recorded were less than factory loads.
I am using CCI 400. Some extracted cases with low charges had rounded edges at the firing pin ident while others were flatter but still with a perfectly visible and normal indentation. What could cause primers to be ejected from the primer pocket? There was no extraction problems either.

Vectan SP3 is close to Alliant 2400 and Vectan Ba9 is close to Unique, tough neither are quite identical. SP3 is spherical and Ba9 looks like, well, Unique...

Barrel: 10.5" Starline brass. Light crimp.

Bullet: Hornady V-MAX 110gr. OAL 53mm. SP3 19gr: 2067fps (factory: 2221fps).
Bullet: PPU 139gr. OAL 54mm. SP3 18.5gr: 1939fps.
Bullet: Hornady Interlock 180gr. OAL 56.5mm. Ba9 7gr: Not enough to cycle (AR), no reading.
I was looking for a subsonic load for the Interlock bullets...

This missing primers business has gotten me worried, never seen that before, though I have never reloaded real rifle ammo before (lots of experience reloading handgun ammo).
UPDATE: After further inspection it appears that both factory (Hornady) loads and my handloads were missing primers after extraction, but most of the Hornady brass were missing the primer while only a few Starlines did. 20 out of 50 cases had missing primers.

Gil.
 
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Factory ammo should not be loosing the primers.

1.Excessive headspace.
2. Over gassed. Close the adjustable gas block.
3.Suppressor in use? Over gassed.
4. Handloads- reduce the powder charge. Are primer pocket now loose & will not hold a new primer.

Just guessing.
 
Thanks, suppressed for some shots, though I don't know if those were the missing primers... I guess it has to be a bit over-gassed to cycle reliably with subsonics and supersonics... I haven't reloaded them yet so I don't know if the pockets are loose...
Gil.
 
Factory ammo should not be loosing the primers.

1.Excessive headspace.
2. Over gassed. Close the adjustable gas block.
3.Suppressor in use? Over gassed.
4. Handloads- reduce the powder charge. Are primer pocket now loose & will not hold a new primer.

Just guessing.
My first guess was #1
 
Hello, thanks for your replies.
The gun is factory assembled.
I reprimed the cases after resizing and the primers would not insert for half of them...
Interestingly enough it's on the Hornady factory ammo brass that this occurs.
I could reprime all the Starline brass but one.
The primer pockets look all right... What does that mean?
I ordered a primer pocket reamer but that might not be the best answer to that issue...
Gil.
 
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Looks like your Hornady brass had crimped primers, that'd explain why you're having trouble seating new primers.

On the other hand, the whole point of crimping in primers is that they're not SUPPOSED to back out. :scrutiny:

I'm lost...
 
Vectan SP3 is close to Alliant 2400
2400 is faster. Chart has IMR 4227 as close. 20220912_100102.jpg

Bullet: Hornady V-MAX 110gr. OAL 53mm. SP3 19gr: 2067fps (factory: 2221fps).
Hodgdon online data has 19.0 grs of IMR 4227as starting load. 2120 fps velocity from a 16" barrel @ Hodgdon data websire.
Your 10.5" barrel will have velocity lower then a 16" barrel. About 30 to 50 fps less per inch.

2400 is not close. 2400 is a lot faster powder then IMR 4227.


My guess is SP3 @ 19.0 GRS is an over pressure loading with Hornady 110 gr bullets?
With SP3- 110 gr - 17 grs may work?

Enlarged primer pockets is a sign of high pressure. Adding a suppressor may increase pressure also?
 
Thank you! I actually did use that first .300 Whisper document. I wonder however if it would be safe to go down to 10.4gr for the Interlock 180gr. The data I have, part of the same first image/article, does list Ba9 but not SP3 for lighter loads... I have never seen light loads of SP3 for other calibers.
17.5gr of SP3 with the V-MAX produces 1950 fps, 1852fps with 16.5gr so 17gr might be around 1900, which is much lower than the factory 2221fps. My 19gr load is still 0.3gr lower than that .300 Whisper max load, and the chrono seems to confirm that, though I know there is really no direct correlation..
BTW I did chrono the Hornady SUB-X 190gr in my 10.5" barrel: 1034fps and very quiet with a suppressor. I haven't bought those bullets for reloading yet because of cost, 68Euros per 100. Note that a $500 AR-15 sells for $1100 here...
I yet have to play with the adjustable gas port and powders like Vectan A0 and A1. Sometimes we can find Vihtavuori here, but none of the U.S. powders. This is my first AR and first time reloading a "real" rifle caliber (I don't count .32-20). I will post further experiments on this thread.
Thanks again for your suggestions and time, much appreciated..
Gil.
 
Hello. I have not tried A0 but did try Ba9. I could not make my AR cycle using Ba9. Ba6-1/2 does work better in that regard.
I tried from 5.5gr to 7gr of Ba9 with the Hornady 180gr Interlock (OAL 56.5mm); no chrono times, sorry. A heavier bullet might cycle.
Here are my other findings, use at your own risk, these are experimental loads:
300blk1.jpg
* Doesn't cycle.
 
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