.308 caliber bullet hard to eject non fired cartridge

[JR Hartman]

Not the first loads for this rifle by any means.

I have loaded mostly 174 grain bullets loaded just off the lands and they have been excellent, but they are expensive for poking holes in paper at fun matches or plinking.

So, I bought a bag of cheap 147 grain fmj projectiles.

Loaded a few up, seated to cannelure.

Tried a few and they seem very tight, and very hard to extract the non fired rounds.

There is faint but clear rifling scribed on the bullets.

These are easily visibly shorter than the 174 grain ammo, but it appears to be touching the rifling!?

what gives?

Oh, its in a K31 Swiss rifle. its called 7.5x55 but its a .308 projectile.

 

[flyr]

The ogive may have a larger dia. further ahead on the 147gr than the 174's.(different shaped bullet) so it hits the rifling sooner.

 

[Boomer686]

Regardless if the bullet looks shorter: measure the COAL. Is it longer than what the book calls for ? If not I would tend to agree with flyr's suggestion.

 

[tiriaq]

It is my understanding that the 7.5x55 chamber has a short throat. You'll have to seat the bullets so that the ogive is not jammed into the rifling. You will have to determine if seating this bullet deeper is practical.

 

[diopter]

Unfortunately, most of the American Cartridge Overall Length reloading information is for the older Swiss Service rifles which have a longer throat than the K31.
https://www.tapatalk.com/groups/the...hurdle-for-7-5x55-in-the-k31-t6627.html#p6284

Some European reloading data use the GP31 title for K31 loads.

http://www.vihtavuori.com/en/reloading-data/rifle-reloading/7-5-x-55-swiss-gp31.html

 

[IvoB]

seat the bullet back some more and make sure that your cartridge OAL is where it needs to be

 

[Ganderite]

The book OAl has nothing to do with your rifle. It is telling you to seat the bullet deeper. Don't argue with it.

The resulting cartridge will look funny. Welcome to the K31.

 

[tjhaile]

I definitely concur that most bullets will have to be seated pretty deep to properly fit a K31. As with anything else, use an OAL that fits your gun, rather than what the manual specifies.

 

[JR Hartman]

Ok, I'll seat em a bit deeper. I have loaded and shot at least 200 174grn and 168grn, as well as a few 176grn bullets. the 174grn were Berger match, and the others were Hornady with poly tips. No problems at all.

Just seems weird to me that a decidedly smaller pill hits the lands before a bigger one, especially because I didn't use K31 specific bullets for the first whole lot of ammo.

 

[diopter]

Visual representation
174 & 168gr looks like:

147gr looks like :

 

[Suther]

Visual representation
174 & 168gr looks like:

147gr looks like :

Lmfao

 

[JR Hartman]

LMAO, thanks man!! I also love old military aviation so its cool.

I would have used an F-104 for the first one and Polikarpov I-16 for the second one

 

[K-C]

If you take a sized (ready to load) case and then dremmel a slit in the neck from mouth to shoulder, you can press any given bullet type into it and then gently chamber it. Carefully extract and measure the COL. Repeat several times to prove consistency. This will be the maximum COL for that bullet type to touch the lands in your K31 chamber. Reduce the actual COL by approximately 0.020" to 0.030" and you should be good to go for that particular bullet.

On a side note, X-Reload sells General Dynamics 147 gr .308 bullets here: https://x-reload.com/general-dynamics-m80-30-cal-308-fmj-bt-147-gr.html

I bought 500 for future .308 Win plinking use - at 29 cent each, you can go wrong (or can you?). I got round to hand loading 100 for that purpose (approx Ball, M80 loads).

I fired 20 and dismantled the other 80. WHY?? HORRIFIC ACCURACY - 10+ inch group at 100 yards! Further investigation revealed that these bullets are sized 0.306 +/- .0005" (General Dynamics factory rejects I assume)

However, there is a bright side - 0.306" is just what the Swiss Doctor ordered

 

[jethunter]

It is my understanding that the 7.5x55 chamber has a short throat. You'll have to seat the bullets so that the ogive is not jammed into the rifling. You will have to determine if seating this bullet deeper is practical.

This. ^

K31 is known for having tight throat. seat the bullet deeper and carry on.

 

[mbogo3]

What I did/do with mine is a fired or unprimed brass.Size it then insert a sharpie colored projectile of your choice seated out there.Chamber and check for rifling marks on the bullet ,if yes recolor seat deeper and repeat until it chambers with no markings or resistance.You need to make sure the test round will fit the magazine length.Now you can set your dies and work out loads.Some will cut a slit in the empty cartridge brass neck to shoulder so the bullet can freely back into the case when chambering.I'm shooting under 1/2 " groups with mine with IMR 4895 and 150gr Win PSP........great for tilting deer............Harold

 

[JR Hartman]

thanks for the heads up on the .306 bullets.

As for making a chamber gauge inert cartridge, I know that, its how I made my 174grn and 168 grn stuff and it works great.

I figured that a lighter and shorter bullet be just fine. Live and learn.

thanks all.

I did crimp these with a Lee Factory Crimp die, into the cannelure, so I hope I can seat them deeper enough to not jam the lands.

 

[diopter]

7.5x55 in not .306" diameter.
GP(18)90 & GP(19)11 measure that only on the exposed part right in front of the cannelure because the bullet tapers all the way to the boat tail which is 7.82mm/.308"

and GP90

 

[mbogo3]

You can just use standard .308 dia bullets with no problems.

 

[JR Hartman]

I suspected, and after I read that other post about the .306 I went and measured. yea, .308

I wouldn't have bought the thing if it took a weird and hard to find bullet.