Thoughts on Cases Failing to Extract

[FALex]

Alright everyone, I've got an interesting issue here. Rifle is chambered in 6.5CM. I am able to fire Hornady brass without any issues. However, when it comes to Lapua brass, I am getting some failures to extract. Let me start from the beginning. I took Lapua brass fired out of my bolt gun and FL sized them. They would not even chamber completely, so I purchased a 6.5CM small base die.

The SBD shrunk the cases down and even knocked the shoulders back to almost Lapua's factory spec, which was 1.557". I could chamber a brand new case and extract it easily. When I hit the fired cases with the SBD, they would chamber, but extraction was a bit tougher as it took a decent amount of pull on the charging handle to get them out. These were coming in at 1.558ish. I believed that under the pressure of the system, these cases would still extract, so I went and tested 10 rounds.

Out of the 10 rounds, 5 would extract and 5 would not extract. The length of the shoulders on them didn't seem to matter. A couple of the cases that extracted had shoulders that were .0015-.002 longer than some of the cases that would not extract. The OAL of the cases was still far under the max trim-to-length, averaging 1.915". Neck wall thickness was averaging .015-.016. Hornady was averaging .014.

Anyhow, I'm sitting here banging my head against the wall because I'd love to use Lapua brass in this rig, but is it just a "no-go?" Have any of you guys experienced something like this with Lapua brass in your gas guns?

Anyone have a line on a metric shit ton of Horndady or Starline brass? LOL!!

 

[nn8734]

What is your load receipe with Lapua and Hornady brass? Using H4350 or another powder?

How much are your fired Lapua cases expanding at the base of the case right above the extractor groove compared to unfired?

Any pressure signs on the case head/primers?

I could be to totally wrong but perhaps your load with the Lapua brass is over pressure whereas the Hornady brass is functioning fine as it’s case walls are on the thin side thus more available case capacity and consequently less pressure.

 

[sinister]

You've told us absolutely nothing about your rifle, bullet, and load.

 

[Yondering]

You've told us absolutely nothing about your rifle, bullet, and load.

My thoughts too. Need some actual details.

Regardless, if you aren't into some wild high pressure loads, usually difficult extraction means a rough chamber, unless it was also difficult to close the bolt in which case it's a sizing issue. Those are two different things though so it's important to differentiate which. Do the unfired cases extract easily?

Edit - re-reading your post it sounds like some of your unfired rounds would not extract easily by hand. You need to do some careful measuring and comparing of your sized brass compared to fired brass from that chamber to find the problem - what measurement is similar or maybe larger on the loaded rounds? That'll tell you the problem. Your loaded rounds might be too large at the neck and binding there.

 

[supercorndogs]

Measure your body diameter in three places, middle below the shoulder and above the base. Size and measure the difference between your SB and standard FL die. You might just have too big of a small base die.

 

[FALex]

You've told us absolutely nothing about your rifle, bullet, and load.

Because it's not important, and you should have extrapolated from the information provided that loads loaded with Hornady brass fired. The rifle is brand new outside of a barrel break in, where it fired and extracted a very weak load that consisted of 36.0gr of Accurate 4350, Hornady brass, pushing a 155gr Speer pig out of the barrel doing all 2250fps.

This issue sprang up during load development. I started at 40.8gr and loaded in .2gr increments that ended at 42.6. The loads at 40.8, 41.4, 41.8, 42.4 and 42.6 were the loads that would not extract.

@supercorndogs - I did measure the bodies of these cases. When I first hit them with the FL die, they shrunk a small amount. I noticed that the taper toward the neck was getting larger, which is right where they looked like they were hanging up. When I got the SBD, the rest of the case, and that portion of the base all got hit, and shrunk everything by about .001, which was the same as the Lapua factory cases.

 

[supercorndogs]

Color one with a marker and chamber it. That should show where its sticking.

That sounds pretty hot for a gas gun in Lapua brass. I think most people are getting about the same velocity with 41.something in Lapau brass as they were with 42.something in hornady brass. I think most top out around where you started in gas guns.

 

[Earnhardt]

Barrel length?
Gas system?
Buffer weight?
Spring?
Bcg brand/weight?
Bolt/ firing pin?

Quick loads says with a 155 grn bullet, with 40.2 grains of H4350 you’re at 52,500 psi
With 42.6 grains of H4350 you’re at 59,500 psi
Doesn’t Lapua brass have a smaller internal capacity than Hornady brass, since it’s built thicker?
Therefore doesn’t the same amount of powder in Lapua brass create higher pressures than in Hornady brass?

 

[nn8734]

Barrel length?
Gas system?
Buffer weight?
Spring?
Bcg brand/weight?
Bolt/ firing pin?

Quick loads says with a 155 grn bullet, with 40.2 grains of H4350 you’re at 52,500 psi
With 42.6 grains of H4350 you’re at 59,500 psi
Doesn’t Lapua brass have a smaller internal capacity than Hornady brass, since it’s built thicker?
Therefore doesn’t the same amount of powder in Lapua brass create higher pressures than in Hornady brass?

Yep, Hornady has the thinnest walls of any 6.5 cm brass I’m aware of. By contrast, federal brass has the thickest ive seen. So thinner walls, less pressure.

Reading the OP, I think he’s simply over pressure.

 

[Jackalope]

Reading the OP, I think he’s simply over pressure.

Sounds like it. Especially since the top two charge weights were the problem.

 

[2aBaC̶a̶]

What velocities was the test and specifically stuck cases?

Measurements on the base above the groove for the 5 that extracted and 5 that didnt?

 

[FALex]

Sounds like it. Especially since the top two charge weights were the problem.

Actually that’s not true...the first that stuck was the most minimal charge at 40.8.

Barrel is 22”, this is a gas piston system. Rifle length

My gut is telling me it’s something with the sizing of these cases. Remember, they do not extract as easily as factory Lapua cases when I just chamber and extract them (without firing). It takes a decent amount of pull on the CH to extract these cases.

 

[Yondering]

My gut is telling me it’s something with the sizing of these cases. Remember, they do not extract as easily as factory Lapua cases when I just chamber and extract them (without firing). It takes a decent amount of pull on the CH to extract these cases.

Then it should be really easy to figure out where they're sticking. As suggested above, color or smoke a case and chamber it, then pull it out and look where it's rubbing.

Seems like you've been running in circles without starting with the most basic things to figure this out.

 

[iceng]

Can you run a test for me ?

Sizing die in press, lapua brass in. Send brass into die, press as normal, extract brass, then rotate it 1/3 (roughly) to 1/2 a turn in the shell holder, and send it back up.

Try that. Does it make a difference ? Small primer lapua and large Hornady ? I'd honestly try a silly low charge, like the book minimum or starting charge weight and load 5. Check velo and report back.

 

[nn8734]

@FALex in your OP, you stated you were able to chamber and extract an unfired factory round that used Lapua brass, correct?

If so, measure the case head to shoulder and web diameter of the factory rounds then simply set your sizing die up so that it duplicates those measurements in your 1x fired cases that were used in your bolt gun. Then follow supercorndog’s advice marking up the brass to see where it sticks.

just a wild ass, a priori guess but I think you’re not bumping the shoulder back far enough and that this gas gun has a slightly shorter chamber than your bolt gun.

You’d probably have your problem solved by now you had limited your original post to rifle, load descriptions and ended with in your last two sentences in post #12.

 

[FALex]

Thanks all for the ideas guys. In hindsight, my OP was missing some info. My apologies if I came across as being argumentative in the past posts.

Check this out:
40.8 - 2630 stuck
41.0- 2644
41.2 - 2661
41.4 - 2664 stuck
41.6 - 2667
41.8 - 2697 stuck
42.0 - 2695
42.2 - 2716
42.4 - 2721 stuck
42.6 - 2740 stuck

Other than 41.3, 41.9 and 42.3 being really good nodes, I'd still love to get this brass deal figured out.

@iceng yes, this is SRP Lapua and LRP Hornady.

I've got a kind of off-the-wall question about FL and SBD shoulder bumping...these are both Redding products. I was always told that you screw those dies in until they make contact with the shellholder and never anymore. Bigjake informed me that this was not true, and taught me that I can screw them in about an 1/8th of a turn more to bump the shoulder back more. Do you guys turn those dies in more than that?

I will try the ideas in previous posts today and I'll update.

I appreciate the input.

@2aBaCa I will get those measurements today and put them in an updated post.

​

 

[nn8734]

Thanks all for the ideas guys. In hindsight, my OP was missing some info. My apologies if I came across as being argumentative in the past posts.

Check this out:
40.8 - 2630 stuck
41.0- 2644
41.2 - 2661
41.4 - 2664 stuck
41.6 - 2667
41.8 - 2697 stuck
42.0 - 2695
42.2 - 2716
42.4 - 2721 stuck
42.6 - 2740 stuck

Other than 41.3, 41.9 and 42.3 being really good nodes, I'd still love to get this brass deal figured out.

@iceng yes, this is SRP Lapua and LRP Hornady.

I've got a kind of off-the-wall question about FL and SBD shoulder bumping...these are both Redding products. I was always told that you screw those dies in until they make contact with the shellholder and never anymore. Bigjake informed me that this was not true, and taught me that I can screw them in about an 1/8th of a turn more to bump the shoulder back more. Do you guys turn those dies in more than that?

I will try the ideas in previous posts today and I'll update.

I appreciate the input.

@2aBaCa I will get those measurements today and put them in an updated post.

​

Why are you over-complicating this? It’s easy.

1) Screw the die down until it hits the shell holder (ram all the way up).
2) Lube and size a case
3) measure the sized case (case head - shoulder)
4) compare to measurements of your precious fired Lapua cases in your gas gun (remove spent primers before you measure the previous fired cases)
5A) longer case head to shoulder? Screw die down incrementally until it sizes it to the same then screw it down again until it’s case head - shoulder datum is .003-.004 shorter than the previous fired cases.
5B) shorter than previous fired cases? Back the die off, grab another case and repeat until you get to .003” bump less then fired cases then proceed to step 6.
6) once you have sized the case to the .003-.004 less than previously fired cases, mark with sharpie and chamber it. Post a pic of the sized, marked case along with whether it was able to chamber/extract normally.

 

[2aBaC̶a̶]

Screwing the die in until it touches is a rule of thumb. You'll have to go more or less depending on where it puts the shoulder.

Maybe somone already mentioned this but take a case that doesnt chamber easily and color the whole thing with permanent marker. Chamber it a couple times like normal and inspect for where the marker is worn away.

Post pics.

 

[iceng]

Good work so far. You CAN screw your die in, make it touch the shell holder and then screw it in 1/8 turn. Over camming or over bumping. Depends on your press, but totally normal.

Someone suggested marker, which I agree with.

This is a long shot, but years ago I chambered a gun for a customer and his brass was too long, it was pushing the case mouth, and swelling the shoulder and causing crazy ejection issues. Trimmed brass to spec, it went away. From memory it was like 308->260rem cos he couldn't get brass or something, he neck turned, but didn't trim.

Lastly, check head space with gauges. I'm leaning towards tight chamber. I've trimmed shell holders and the bottom of dies to allow enough bump a few times for people who insist on super tight chambers, who then can't size brass to work.

 

[FALex]

Below is a case that was hit with the SBD, brought shoulder down to factory Lapua spec. Oddly enough, this one did not even chamber completely and needed assistance from my cleaning rod to be extracted. These cases are measuring, on an average, .005" wider at the junction just below the rim of the case. I'm assuming that's why that color is remaining on the case. It's not fully seating into the chamber. A factory fresh Lapua case measures .468 at this same juncture. Fired-then-sized cases (even in the SBD) are still coming out at .473 at this juncture.

@nn8734 - I've reloaded for precision gas guns for almost a decade. Want to know how much I have to bump my shoulders on my JP LRP-07's brass? I screw the die in until it touches the SH, then back it out about 1/16th of a turn, so the shoulders do not move at all. For all of my other gas guns (KAC's, Larue's, DRD, SCAR's, ACR's, et al...) I screw the FL die in until it touches the SH and lock it down there.

I know it is commonly typed about on the internet, about bumping shoulders .002-.003" for gas guns, but in 10 years of doing this, with a vast multitude of semi-automatic rifles, I have never had to bump my shoulders like you and many other have been typing about. Ergo, I have never had to screw the FL die in past the SH contact point.

I am well aware that bumping the shoulders improves chambering and extraction. I am also well aware that mitigating the amount of bump, while ensuring both of said processes, dramatically increases the life of my cases. Regardless, in this instance, moving the shoulders WAY back (too far, IMHO), is not helping.

 

[nn8734]

@FALex yea, I know how long you’ve been reloading because I’ve read your biography here on the Hide. Christ. As far as shoulder bump do whatever you want. You fucking asked specifically about die set up and I answered it.

This is exactly why I don’t help people with reloading anymore.

hope you figure it out as you seem to have all the fucking answers except for where it counts.

 

[FALex]

@FALex

This is exactly why I don’t help people with reloading anymore.

So you went back on your sacred oath to drop into my thread or did I just happen to catch you at your stopping point? LMAO!!

I guess Redding manufacturing and selling shellholders that control for the amount of shoulder bump is just a moot point then right? Especially when you can just keep turning the die in.

"Just screw the die in until you get the amount of shoulder bump you need, or snap your press linkage, whichever comes first!"

I, as well as many others, will be saddened by the wealth of reloading information you will not be bringing about on the internet anymore.

 

[iceng]

Wow that brass looks bad. If it's a brand new chambered barrel, send it back for eval. It seems WAY wrong on spec.

I've seen winmag and Glock bulge / base swager, (or squeezer) but not CM.

It's so tight I'd be half tempted (if it was mine) to drop a reamer in and hand spin it, see if it licks anything out. I have seen this on some other Smiths chamber job where the angles were all janky. Headspace worked, but it wasnt "nice". Turns out it was a multi reamer job to cut th chamber and was just wrong. Licked with a reamer and BAM smooth sailing.

Pull the barrel, take to a Smith with Your bolt, check head space then get them to drop a reamer in and give it a turn or 2 and see what happens.

 

[Yondering]

What in the world did you color that case with, a whiteboard marker? Try using actual Sharpie and clean the lube off the case first. It won’t rub off like that, and will give a much better indication of where it’s rubbing.

Also, the point was to do this on a loaded round that has trouble chambering. Don’t fire it.

Honestly I understand why some of the other people here sound frustrated. Many of the guys who responded to you could have figured this out in about 10 minutes by themselves and have given good advice, but you seem very resistant to it.

 

[iceng]

Some people have trouble articulating what their issue is, and also translating instructions to real world use.

Frustrating indeed, however I want to see how this ends. If we both learn from this, then I can potentially help the next person WAY quicker. That or abandon the thread earlier.

 

[nn8734]

So you went back on your sacred oath to drop into my thread or did I just happen to catch you at your stopping point? LMAO!!

I guess Redding manufacturing and selling shellholders that control for the amount of shoulder bump is just a moot point then right? Especially when you can just keep turning the die in.

"Just screw the die in until you get the amount of shoulder bump you need, or snap your press linkage, whichever comes first!"

I, as well as many others, will be saddened by the wealth of reloading information you will not be bringing about on the internet anymore.

Not a Mark Twain fan, I see...

I now understand why you can’t figure this simple problem out by yourself. Wouldn’t be surprised in the least if I learned you actually broke your press by screwing a die down as far as it will go then sized a case.

You’re a clear cut candidate for natural selection, hope it happens sooner rather than later, for all of our sakes.

To everyone else: sorry I couldn’t resist. Falex-the-dipshit will go back on ignore and I’ll not post in this dumpster fire of a thread any longer.