Hi Pressure ?

[Bassfish1952]

Took my new cz out today did 40 rounds of Hornady 103 ELD-x 6ARC

I had 2 problems, Hope you guys can help with 

1st.   Very hard to work bolt after each shot. going forward with fresh round no problem very smooth and easy. After the shot it was hard to flip lever up and hard to pull back. Again this was with factory ammo.
This rifle was a 7.62x39 before barrel change and did not do this with that ammo.

2nd. I am using factory 7.62x39 Mag's both of the mags were hard to load and when using did not want to pick up a round after ejecting the fired round. worked ok with 2 rounds but started getting bad after 3 rounds in the mag.. I only hunt so 2 rounds work for me but I don't like something that doesn't work the way it should

This was a cz527 action with the pac-nor barrel . 

Thanks for any feed back on this

[grayfox]

What's the condition of the fired brass? Any pictures, especially of the base, ejector swipes, etc.
Take 2 or 3 and resize them, looking to see if it's especially hard to do.
Does sound like an overpressure to me, but would be more likely due to a cramped headspace. I've shot several 103 eldx factories, from gas and bolt, and haven't seen any hard bolt lifts.

[CZ527 Guy]

Have a idea or two on mag issues. Expect the issues you are experiencing with not picking up rounds may be due to improperly seated magazine well when re-assembeling the rifle in the stock. See video below. You can ignore the 1st 13 minute or so that revolves around adjusting set trigger / set trigger. near the end of video you can see how it is easy to have assembled the magazine well canted or binding. which prevents fully seating the Mag well.

When you assemble the mag well with the empty (no live rounds) mag. some how this aids greatly in preventing the binding that prevents proper seating of the mag well.

https://www.youtube.com/watch?v=BqcwFciaVbc

if the mag well is insufficiently installed the rounds will sit low & fail to pick up when cycling the bolt. in another video that touches on tweeting the magazine. I vaguely recall having adjusting my spring that did improve how the magazine feeds. The video frankly is not as helpful as id hope for though may help so ill offer as a starting point.

https://www.youtube.com/watch?v=BqcwFciaVbc


Regarding the heavy bolt lift &tough extraction I am stumped at least for the moment. Brass looks fine from what I am observing. do not expect pressure issues. Think I might give Pacnor a call on this one. Do I recall correctly that the 105 gr ammo was less of an issue or no issues?

If I am correct about the mag well being installed incorrectly then perhaps this may be a factor in the bolt lift. Honestly I doubt it.

[Old Bob]

Didn't Hornady's original loading for 6mm ARC 103gr ELD-X ammo have their bullets seated too long causing high pressure issues? Bassfish, do you know if the ammo you have is new production that has their bullets seated deeper or some of Hornady's first production stuff?

[CZ527 Guy]

Another way to adress the OAL question is to see if Bassfish has a caliper to verify over all length of factory loaded 103 gr ELDX ammo. 103 Gr ELDX OAL should run 2.245" per my Hornady load manual.

[grayfox]

OB the original issue with factory cartridges being too long was with the 105 Hpbt, Hornady Black 105's. I don't recall the 103's having that issue...

[CZ527 Guy]

Suspect if this is high pressure we are talking mild high pressure. In any case this is a bit surprising in that the round is to be loaded for 10,000 less pressure than the bolt action is meant to take.

Suppose this may be one of the reasons I favor hand loaded ammo as i can taylor loads for my rifle. When I ordered the Pacnor barrel for my rifle I was offered choices of rifling configurations (fast or a slow barrel) Due to case capacity & factory loadings being intended for the lower pressure limit AR offerings, I chose the fast barrel. Fast barrel would also equate to a rifle that reaches pressure limits at a lower powder charge weight.

If I recall correctly a light, sticky bolt lift was not un common with factory loaded ammo in my rifle as well.

[Bassfish1952]

Another way to adress the OAL question is to see if Bassfish has a caliper to verify over all length of factory loaded 103 gr ELDX ammo. 103 Gr ELDX OAL should run 2.245" per my Hornady load manual.

looking now 2.24 everything I have bought has been in the last 6 months and my are cheap calipers but reading 2.24 even , checked 20 in a box that was bought same time as the ones used 

Lot # 3223336.  and fired ones were Lot # 3223422 were bought at same time from same dealer

[Bassfish1952]

Well group at 100yds was .84 and I had no other problems . would a modified case and an oal gauge tell me anything ? Or any suggestions 

I don't think its unsafe to shoot so I will continue to shoot and see what develops 

Still planning on using it in January to hunt

Looked at those YouTube videos could be the cause I will work on that, I know one thing the tip of those 103's will put a hole in a finger if you slip while loading the mag.

also the only thing I dislike about the cz527 is the mag sticking out just where I want place my hand to carry . I saw on the web a site the cuts down your mag to mount flush with the stock , I think will carry 2 or 3 rounds I may do that also


Thanks
 
I'll keep trying and I will give Pac-nor a call 


Question 

The fired brass is the same as unfired brass , from what I have been reading on here shouldn't there be some stretch ?

I measured both a new unfired and the fired case both were the same ?

[CZ527 Guy]

Suppose I would expect .002" to .004" growth for each firing. So first firing may be easy to overlook.

[Bassfish1952]

Suppose I would expect .002" to  .004" growth for each firing. So first firing may be easy to overlook.

Thanks
I may have to get a better set of calipers , I got these on Amazon for checking something on my boat . Didn't need this degree of Accuracy .

Now the brass will go in my save for later box .

[Bassfish1952]

Found the problem.

A small amount of the Cerakote got into the neck area of the barrel and was missed by the outside vendor that did the coating.

After talking with Pac-Nor I elected to do the removal rather than send it in for them to do and following their instructions have it almost worked out . Still very happy with the work and barrel .

Even thou we all try to do 100% sometimes little things happen I'm Happy with it.