[041x]

I got my new 8mm barrel and started to heapspace it. I set it to lock up and then I when one click out. I loaded a romy round in the the bolt closed all the way. So I moved the barrel back to lock up (0 clicks out) and load up another romy round and the bolt still closed. With the bolt closed I took a small screw drive and I could move the round forward and backwards about 0.010" I tried some 80 yugo I had and it was the same thing. So I put all my .308 stuff back in and ran it out two click and loaded a round. I was not able to move the round forward and backwards with my screw driver. I've attached two pic one of my .308 barrel and round and one of my 8mm barrel and round. In the .308 pic with bolt pushed all the way forward you can still see a small gap between the extractor lips on the bolt and the barrel. On the 8mm pic the bolt is pushed forward all the way and the extractor lips are hitting the barrel and the round is still loose. Is this chambered to deep?. Is it safe to shoot. I don't think it is safe. I've though about removing 0.020" off the back of the barrel. I wouldn't be cutting into the chamber. It would just have a smaller radius leading into the chamber. I'm going to contact the manufacture before I do this. I had to use up the last of my .308 ammo today Is this normally for 8mm barrels? What do you guys think? Thanks




8mm

.308

 

[kaotic01]

Where did you get the barrel ???? We need to know that first ............

 

[BeltFedPlus]

This brings up a point that I talked about earlier on another thread. A way (perhaps not the best but it works)to check for a deep chamber is, with the barrel out and the chamber clean, drop in a cartridge and check the distance from the face of the barrel to the end of the cartridge head. Check it against a barrel known to be good. I've got a USGI 30-06 barrel that measures .123 and functions perfectly at 2 clicks out. My 8mm barrel measures .115 and functions perfectly at 0 or 1. If the chamber is deep, it may tend to split the necks on cases. Additionally 1919s are designed to run really loose. you're not shooting a target bolt gun. All this to say, that you might have a really deep chamber and the other question was already stated. "Who made it?"

 

[loboslanding]

Ditto, who made it? If it's someone on this board I assume you've already addressed the question to them.

 

[Luke]

Does John McGuires 8mm barrels work fine? How does his 8mm barrels work. How does his measure out according to others barrels.

 

[acmech]

Does John McGuires 8mm barrels work fine? How does his 8mm barrels work. How does his measure out according to others barrels.

Johns new batch of barrels are perfect for 154gr Romanian ammo. However for Yugo they are chambered too short (not throated deep enough). I got yugo cases splitting on me just below the shoulder, returned the barrel, read some threads here, and dropped a loaded yugo round into the replacement barrel. It stuck out noticably more then the Romy round I dropped in. With thumb pressure on the back of the cartridge it wouldn't seat, I applied a black marker to the tip of the bullet and it is hitting the rifling before the cartridge is fully seated, it can easily be seen. It explained why cartridges were splitting, they weren't fully supported in the chamber when fired. The barrels aren't throated deep enough for 198gr yugo ammo, however if you only shoot the 154gr Romanian ammo, this chrome lined barrel will last you a long long time. It's probably the best barrel there is for Romy ammo being chrome lined, however you will have problems with the yugo ammo.

 

[041x]

This is a John M barrel. Thanks for the measurement for how much your shell sticks out, I'll have to measure mine.

 

[striker754]

is my barrel fine for yugo? i did the bullet in the chamber test and measured .115 with romy ammo and .130 with yugo. i believe this is because the yugo has overall longer length than the romy. I covered all the copper on both bullets with sharpie black marker and the yugo has slight scraping at the bottom of the bullet near the case but nothing too bad.

will i be fine to shoot yugo? 1 click out?

 

[acmech]

is my barrel fine for yugo? i did the bullet in the chamber test and measured .115 with romy ammo and .130 with yugo. i believe this is because the yugo has overall longer length than the romy. I covered all the copper on both bullets with sharpie black marker and the yugo has slight scraping at the bottom of the bullet near the case but nothing too bad.

will i be fine to shoot yugo? 1 click out?

You could try it, but is the case supported by the chamber walls? Does it wobble around when pushed in? Mine did and cartridges were splitting vertically near the shoulder. My cases were also sticking out about .015-.020 more on the yugo rnds. On my ammunition store barrel, both rounds drop in like you would expect and the Yugo didn't stick out anymore than the Romy. The only way I could keep the splitting down with the chrome lined barrel was with the headspace set 0 clicks out using the field method. The problem is if the bullet is jammed against the rifling, you will have pressure spikes, there is supposed to be room for the bullet to "jump" to the rifling to develop forward momentum.

Yes, the yugo does have an overall length that is more than the Romy however, it is within spec. according to the sierra reloading manual. If you were going to reload 220 grain rnds for this caliber, the sierra manual gives an overall length of 3.25 inches and the yugo is 3.161 so basically you couldn't reload some bullets to spec. for this barrel because it isn't throated deep enough. I'd stick to using romy ammo. in the barrel.

 

[acmech]

This is a John M barrel. Thanks for the measurement for how much your shell sticks out, I'll have to measure mine.

Coincidently John has already posted another thread stating that the Yugo ammo is garbage and he doesn't want to hear any complaints from anyone shooting it. You'd better stick to using Romy ammo.

 

[striker754]

You could try it, but is the case supported by the chamber walls? Does it wobble around when pushed in? Mine did and cartridges were splitting vertically near the shoulder. My cases were also sticking out about .015-.020 more on the yugo rnds. On my ammunition store barrel, both rounds drop in like you would expect and the Yugo didn't stick out anymore than the Romy. The only way I could keep the splitting down with the chrome lined barrel was with the headspace set 0 clicks out using the field method. The problem is if the bullet is jammed against the rifling, you will have pressure spikes, there is supposed to be room for the bullet to "jump" to the rifling to develop forward momentum.

Yes, the yugo does have an overall length that is more than the Romy however, it is within spec. according to the sierra reloading manual. If you were going to reload 220 grain rnds for this caliber, the sierra manual gives an overall length of 3.25 inches and the yugo is 3.161 so basically you couldn't reload some bullets to spec. for this barrel because it isn't throated deep enough. I'd stick to using romy ammo. in the barrel.

When the round is fully in the chamber, it is the same except for the length sticking out. Yugo and Romy are the same. Each wiggles the same amount although it is VERY slight. Should be fine? go one click out and see how the case does?

My barrel is not a John M barrel, but his post of telling people to not contact him if his 8mm barrel doesnt work with spec 8mm is BS.

 

[Dave B - Great Lakes Arms]

Funny how I said the same things a month and a half ago but I was flamed and labeled a trouble maker.

 

[striker754]

Dave, I think in that other thread you knew alot about barrels, will my barrel be fine?

 

[Dave B - Great Lakes Arms]

Well....I can only speak for myself but......
What I would do ...and did do...is take a few rounds of Yugo and color the projectile with a black magic marker and let it dry... drying type layout blue works OK too. Once dry, put the round in the chamber and apply hard thumb pressure to the base of the round and try and push it in the chamber pretty much as hard as you can. Take the round out and inspect...If you see scrape marks on the projectile the throat is too tight and will casue an over pressure situation when fired which could result in a KABOOM and damage to the gun, personal injury or death.

Sounds like the cartridge is headspacing properly off the shoulder of the case so my personal assessment of the situation is you shoud be OK. Of course this is not a recommendation to do anything.....cuz I don't want to be sued if something else goes wrong and you still have a KABOOM!

 

[041x]

Coincidently John has already posted another thread stating that the Yugo ammo is garbage and he doesn't want to hear any complaints from anyone shooting it. You'd better stick to using Romy ammo.

Romy is all I want run but I having trouble with it. The bolt with lock up when I chamber a round and I have the barrel set at 0 clicks. I've read a few posts where people where having problems with romy cases spliting. I don't think a case in good condition should ever split as long as the headspacing in right.

 

[acmech]

Romy is all I want run but I having trouble with it. The bolt with lock up when I chamber a round and I have the barrel set at 0 clicks. I've read a few posts where people where having problems with romy cases spliting. I don't think a case in good condition should ever split as long as the headspacing in right.

I had a couple cases splitting with my ammo store barrel when using romy, I don't think it might be a big problem, the steel case might not be ductile enough to stretch. If it is every single case, then you will might want to look at something else.

 

[BEFU]

8mm barrel summary

OK, for those of us building a 1919 and are getting a new chrome 8mm barrel from John M:

1. We need to chamber a round and check if the bullet hits the rifling in our barrel to be sure.

2. Odds are that the 198 grain yugo that is currently being sold by Aim and Century will not work. The 198 grain bullet being longer will contact the rifling once it is chambered. This may result in an intense fireworks display several inches from your face. (it would be bad)

3. The John M barrels in general will work with other surplus ammunition. Mainly the Romanian 153 grain.

4. Also, it is my understanding that John has publicly stated that problems relating to the use of the 198 grain yugo should not be directed towards him

5. what barrels are available that will work with the Yugo 198 grn?

Have John M 8mm chrome barrel coming, but not arrived yet. Sale on Yugo is over in a few days at Century, and need to know if I should avoid buying 10k-20k rounds unless I buy a different barrel.

Wow, this gets confusing trying to track info over several threads.

Thanks for all the insight and knowledge guys.

Brian

 

[cal50]

If you do have a barrel the the bullet makes contact with the rifling try seating the bullets deeper. I know it would suck but given the low cost of the Yugo ammo it is still worth it. Buy a Lee cheap die set in 8MM and use the seating die. Personally I have an Ammunition store barrel. I am unsure of the date of manufacture but I was told these were made by ER Shaw barrels. I have a bunch of Yugo and it chambers fine (does not hit rifleing).
I would like to see one of the chrome lined barrels to make a chamber cast to compare the chamber and throat areas. If you knew the chamber reamer manufacture (JGS,Clymer,etc,) you could see the specs.

 

[Dave B - Great Lakes Arms]

Already made a chamber cast of the chrome lined barrel and it is considerably different than the MG34 8mm barrel I also casted. Chamber shoulder is a different angle and length and one land of the rifling goes all they way to the case mouth almost on the new barrel. I could take a picture but it would be hard to see.

This different shoulder geometry could explain split cases. I do not split cases with my MG34 barrels but most aftermarket 8mm barrels do.

 

[striker754]

here are the results from pushing a yugo into my barrel with my thumb as hard as i could.

www.theflyingbullet.com/1919/yugo/

what do you guys think