Semi auto advice needed

[Turpentine21]

When you say cases are .015 longer after being fired in the AR vs the bolt, where are you taking your measurement? Case head to the shoulder with a comparator or simply OAL. Either way .015 is quite a “Stretch”.
I have a pair of Grendel’s that one will leave cases
base to shoulder .007-.009 difference between the two. That extra stretch is tougher on brass. I have to separate cases according to which rifle they were fired in. Otherwise I would be bumping shoulders back to much and working my brass to much.
The one with the longer chamber may get weeded out soon. But I have a couple of things I intend to try before I do that.

 

[aschler]

When you say cases are .015 longer after being fired in the AR vs the bolt, where are you taking your measurement? Case head to the shoulder with a comparator or simply OAL. Either way .015 is quite a “Stretch”.
I have a pair of Grendel’s that one will leave cases
base to shoulder .007-.009 difference between the two. That extra stretch is tougher on brass. I have to separate cases according to which rifle they were fired in. Otherwise I would be bumping shoulders back to much and working my brass to much.
The one with the longer chamber may get weeded out soon. But I have a couple of things I intend to try before I do that.

I have the same problem with two of my 6.8 SPCs, use different brands of brass to keep them seperate. Good reminder I need to check my new 6.5 Grendel as well.

 

[Koda_]

I always thought were werent supposed to shoot handloads developed for one rifle, in a different rifle?

 

[ARlife4me]

I always thought were werent supposed to shoot handloads developed for one rifle, in a different rifle?

Too many options that are safe too do. As long as you're not at max pressure in 1 that could be over pressure in another. But you can use the same load, but also not be as accurate. Lots depends on what you want?

 

[Koda_]

Too many options that are safe too do. As long as you're not at max pressure in 1 that could be over pressure in another. But you can use the same load, but also not be as accurate. Lots depends on what you want?

Im aware that we can develope a handload for multiple or all rifles, but unless we did that from the beginning, isnt it dangerous to expect a handload developed specific for only one rifle to work in any other rifle?

 

[nksmfamjp]

So, it doesn’t “fully cycle”??

Does the bolt move rearward at all?
Does the empty extract and eject?
Where does it eject to?
Does the bolt pick up the next round?
Does it stop just short of chambering?

Basically a DI gun gets gas pressure through the port. It unlocks the bolt. Remaining port pressure….or actually the inertia from the opening burst of pressure moves the bolt carrier assy and buffer to the rear. It needs to go far enough to the rear to eject and allow the mag spring to push the next round to the feed lips. Then going the other way, the inertia plus spring pressure drive the next cartridge in and lock the bolt.

A not cycle diagnosis really requires knowing what completed and what didn’t in the cycle.

Then some of the other questions matter.

 

[ARlife4me]

Im aware that we can develope a handload for multiple or all rifles, but unless we did that from the beginning, isnt it dangerous to expect a handload developed specific for only one rifle to work in any other rifle?

You should always be aware of that possibility. You just never know if the next chambering is tighter or more loose changing the pressures. Measuring might get the answer, but best to back off and start up again.

 

[kfreeze]

Your friend needs to send that barrel back to the manufacturer. Or at least have it checked with go/no go headspace gauges. That's the problem with home builds. Most don't check headspace. I always at least measure the fisrt fired case compared to new or fl sized brass if I don't have headspace gauges. If he wants to reload his case life is going to be poor.

 

[aschler]

Your friend needs to send that barrel back to the manufacturer. Or at least have it checked with go/no go headspace gauges. That's the problem with home builds. Most don't check headspace. I always at least measure the fisrt fired case compared to new or fl sized brass if I don't have headspace gauges. If he wants to reload his case life is going to be poor.

Checking headspace isn't a guarantee you won't be oversizing your brass. I had a rifle that passed a headspace check but still saw the case growth of 0.013" from my resizing die fully seated and 0.012" & 0.014" from unfired brass.

 

[ARlife4me]

Checking headspace isn't a guarantee you won't be oversizing your brass. I had a rifle that passed a headspace check but still saw the case growth of 0.013" from my resizing die fully seated and 0.012" & 0.014" from unfired brass.

That's sad on so many levels!

 

[kfreeze]

Checking headspace isn't a guarantee you won't be oversizing your brass. I had a rifle that passed a headspace check but still saw the case growth of 0.013" from my resizing die fully seated and 0.012" & 0.014" from unfired brass.

No, but when you use different parts from different manufacturers, it's a good place to start looking for the cause of the problem. You issue above is worse than belted mags that I have seen. I would look at different brass.

 

[Jeremy R Snyder]

When you say cases are .015 longer after being fired in the AR vs the bolt, where are you taking your measurement? Case head to the shoulder with a comparator or simply OAL. Either way .015 is quite a “Stretch”.
I have a pair of Grendel’s that one will leave cases
base to shoulder .007-.009 difference between the two. That extra stretch is tougher on brass. I have to separate cases according to which rifle they were fired in. Otherwise I would be bumping shoulders back to much and working my brass to much.
The one with the longer chamber may get weeded out soon. But I have a couple of things I intend to try before I do that.

Sorry should have specified COAL

I always thought were werent supposed to shoot handloads developed for one rifle, in a different rifle?

agree with this if it’s something close to max load…. If you have a load that is on the lower end of the load data so to speak, how is this a problem? I mean when you start a load for a rifle where would you start? Not sure what your post is saying really…

 

[aschler]

That's sad on so many levels!

I noticed case seperation starting after the second reloading; adjusting sizing die depth solved the problem. I threw out the rest of the cases (approximately 50) in that batch so I think the price to learn how to resize properly was reasonable.

 

[cajun]

Every custom gas gun needs an adjustable gas block for this reason. I even had to drill a gas port a bit and choke it down with the block to get it to cycle.