7.62x39 bullets PPU PSP and Hornady V-Max

nullshine

nullshine

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So I started into my first reloads today.

The load data I'm using:
24.9 grains of Reloder 7 (start load)
2.150" Min OAL

I trimmed, chamfered, lubed and then full length sized my cases (Winchester).
Primed (CCI# 200).
Weighed out the Reloder 7 @ 24.9 grains and charged the cases.
Seated a PPU 123 grain soft point, slowly adjusting the bullet seating die until I covered the crimp groove, but was still above the stated minimum OAL.
(This works out to be 2.190", about 0.005" over or under depending on soft point quirks). This all seems good to me, so I applied the factory crimp die (no crimping done while bullet seating).

I also seated some V-Max bullets, and when I set them down in my tray of finished PSP rounds, I noticed the V-Max were significantly longer (using the same settings on the bullet seater die). The rear edge of the cannelure on the V-Max is also about .100" away from the edge of the case mouth (cannelure is exposed).
This seemed weird to me, so I did not factory crimp them yet.

The OAL on the "completed" V-Max rounds is 2.285", so about 0.100" longer than the PSP (using the same settings on the seating die).

The PPU PSP BULLET ONLY is:
0.875" long, the crimp groove starts 0.170" from the base of the bullet and is approx 0.035" wide.

The V-Max BULLET ONLY is:
0.985" long, the cannelure starts about 0.285" from the base of the bullet, and is also approx 0.035" wide.

Based on some measurements with a caliper of the completed(so far?) cartridges and individual bullets, the V-Max bullet, and the PSP bullet should be taking up the same amount of case volume.

So now, finally, on to my question.

Why the heck is the cannelure on the V-Max so far forward? (And why is the bullet itself about 0.100" longer?)
I could ram the V-Max down another 0.100" or so... But that seems like a really bad idea because case volume in the V-Max load would then be quite a bit less, and I would estimate that this would come very close to, if not actually, compressing the starting charge of 24.9 grains of Reloder 7.

If I leave the V-Max load as is, then the OAL of the V-Max load (2.285") is too long to fit in my magazine.

Anyone have an idea of what is going on here, and what I can do to correct it? Or am I sweating the case volume thing too much? WTF.
 
Your last sentence. I load 27 grains of IMR 4198 in Winchester brass using the V-Max set to the crimp groove. No adverse problems whatsoever.

I've even loaded 150 grain Hornaday soft points using 26 grains of IMR 4198, with the OAL the same as the Czech surplus, again, no problems.

I have no idea about the characteristics of the Reloader 7 though, and I haven't seen data using it in the 7.62x39. Maybe you have.
 
Reloader 7 was made for 7.62x39

Here is the loading info from Alliant from my notes.

Code: 
Alliant Powder
Bullet		Case	Min.OAL	Barrel Length	Primer	Powder		Charge (gr.)	Velocity
							
Speer 123gr SP	IMI	2.15	22		CCI 200	Reloder 7	27		2429
 
Thanks for all the responses guys.

Ganderite:
I knew bullets could be a different length, I just wasn't expecting so much of a difference for a bullet in the same weight! Thinking about it now, I guess they need room for the plastic tip and cavity in the V-Max. I'll push that V-Max down another 0.100" or so, and un-bunch my panties. :D
That's inexperience for you!

mkrainc:
Looking at it in a very broad sense, everything I see for load data seems to have 7.62x39 loads using less IMR 4198 than Reloder 7. I saw a chart of relative burn rates which showed IMR 4198 as a faster powder than Reloder 7. If you're using 27 grains with a V-max seated to the cannelure, I don't suppose 24.9 of Reloder 7 is going to hurt anything. I know it's not as simple as that, but it gives me some assurance.

Cmiller:
I remember running into that 27 grain load on the Alliant website a while back. I'm going to chrono my loads and work up to it. I've seen the 24.9 start, 25.5 grain max load in a lot of older reloading books. Another grain and a half seems pretty significant, I wonder if the powder formulation has changed some?

Thanks again guys!
 
In my SKS rifles I shoot all three of the Hornady .310 bullet FMJ,SP and V-MAX as well as several other bullet of different mfg. weights and dia. I seat all the Hornady bullets out to 2.200' per the Lyman #39 manual 2.190' in the Hornady manual,I just load mine out to 2.200" and they feed and function just fine. The bullets ogive on the V-MAX is different than the FMJ and SP so you will have to adjust the seater plug when loading that bullet.

Reloader #7 is my powder of choice because it's readily available and being an Alliant powder it's cheaper than others in the area. I use a standard load of 25.5 grs. with any of the Hornady 123 gr. bullets.

The Max load in the Lyman manuals using Reloader #7 and the Hornady 123 gr. bullets is 26.8 grs. this is not a compressed charge,in the Hornady manual it's 26.6 grs. I've shot 26.0 grs. before but the 25.5 gr. load was more accurate.

The only PPU bullet I shoot in the SKS is the 150 gr. BTSP I use 24.0 grs. of Reloader #7 with that bullet the Lee manual gives a Max load of 24.8 grs. of Reloader #7 with that bullet weight. I use the provided crimp groove on the PPU 150 gr. bullet and the OAL comes out to 2.200" The SKS rifles have pretty deep throats so even if you load out a bit longer it not and issue the real issue is the magazine when loading it out to long.

A couple different loads I shoot in my SKS rifles.
A.jpg

Picture016.jpg

SKS150Gr.jpg

Cast.jpg


For brass I use Lapua berdan primed,Winchester,PPU LR and Remington SR primed cases. For the boxer primed brass due to the free floating firing pin in my SKS rifles I use the CCI #34 mainly but my Chinese SKS will function just fine using Win. LR primer My Yugo doesn't like the softer commercial CCI primers.
 
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