XL750 Priming Issue

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peeplwtchr

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Hi All -

This last round of loads I experienced a far higher rate of primer seating failures than usual, about 4-5%. The primer cup and ram are clean, which makes me think it must be the brass, however only about 1/2 of these are crimped. This press has always done a great job with crimped brass. The primers are CCI, which aren't as soft as winchester. And the upside down thing is brand new, after about 7k rounds through the press. Anyone got any leads?

Thanks!
 

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Is it possible you have the large primer tube in the armored vertical magazine? I'm wondering if that might explain small primers getting flipped over or even sideways as shown in the picture.
 
If your primer tube is the right size, next is to make sure your primer slide is timed right and moving freely, all the way back. You may have to adjust the clamp on the mount, and the location of the rod when it rides up. Make sure cup is centered in toolhead by loosening the screws, and push handle foreward, then tighten. Next with no primers in the tube, use a pen light to look straight down tube from top with handle straight down. Make sure cup is centered in tube. Use the allan nut to adjust it.
 
Don't suffer in silence! If your problem still exists, call Dillon in the morning. They will walk you through a ''fix'' or have you send the part back for them to repair. Dillon is that good!
 
I was having a similar issue...my primer slide was dirty causing the slide to hang up then jump/stumble just enough to jostle the primer. I removed the parts and cleaned in accordance with the manual. I seem to remember the plastic piece was pretty gunky...
I stopped mass depriming on the 750 when I purchased an APP. Haven't had an issue since.
 
Had same issue on my 650 on two different times, (1) shell plate too lose (2) wrong locator pins causeing shell plate to bind and primers to jump around
 
You should ream or swage your primer pockets if they are crimped. I don't let new brass (either from range pickup or even fresh starline) into my cycle of cases without a light spin of pocket reamer. With hard primers like CCI even new starline sometimes gets caught momentarily on the shoulder when priming.

I was frustrated with my 750 priming until I fit the brass primer magazine tips to mine from UniqueTek. I don't even need the follow rod any longer. Filling the primer tube 100 at a time also seems to help.
 
Unique Tek tips most definitely, throw away the plastic ones.
 
I have had results like that, if the bench is “springy” and there is “sticking” in the dies or powder funnel.

When the bounce occurs as the resistance is overcome, the primer that was right flips, in the cup, then you seat the incorrectly oriented primer.

Lube your cases, so the process is slicker/get a more ridged bench.

Completely sideways and inverted primers have never been caused by crimped pockets, I have tried to force them into. They are still mangled but the results are different than the photo you posted.

If you never had the problem before but just started wet tumbling, lubing would cure the issue or going back to dry with polish.
 
Completely sideways and inverted primers have never been caused by crimped pockets, I have tried to force them into. They are still mangled but the results are different than the photo you posted.

I would get sideways primers like that sometimes when trying to force CCI LPP into IMI crimped 45auto LPP brass using the priming system on my Redding T7. Not fun when it gets stuck in the shell holder.
 
Forgot to mention, when I use my xl750, the primer cup is very easy to see the placement of the primer in the cup as you raise the handle, especially when you have and upside down primer.
See if you can watch it as you load, sounds like you are beat before you start the priming process as the primers aren’t in the cup properly to begin with.
 
Forgot to mention, when I use my xl750, the primer cup is very easy to see the placement of the primer in the cup as you raise the handle, especially when you have and upside down primer.
See if you can watch it as you load, sounds like you are beat before you start the priming process as the primers aren’t in the cup properly to begin with.

That's what's puzzling. A primer cup check is the second step of every handle pull, without exception (Just like the powder drop visual check).
 
That's what's puzzling. A primer cup check is the second step of every handle pull, without exception (Just like the powder drop visual check).

I would definitely look at timing. Sometimes on the 750, if your shell plate is too tight, it won't be quite centered, and it will tip the edge of the primer and turn it. You have to find that fine line between tightening the shell plate down until there is no play, but it still indexes completely and sits in the detent. The key is to double triple check all the adjustments, make sure the slide is lining up front and back, the primer rod is adjusted correctly, the primer is dropping clean into the cup, and when you go forward, the shell plate has firmly set on the ball before the primer is seated. Both my 750s came with the slide way out of adjustment. The good news is, once you set the locating screws, it's been probably 15 or 20k rounds and I haven't had to mess with it again.
 
Hi All-

Thanks for the help. I discovered that one of the primer assembly screws was loose, the one closest to the press. I did check it initially, but obviously not very well. Just loaded 400 without a single primer issue. This thread was good at listing all the possible causes, thanks again! Oh, I also loosened the shell plate again, which wasn't even sticking.
 

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Hi All-

Thanks for the help. I discovered that one of the primer assembly screws was loose, the one closest to the press. I did check it initially, but obviously not very well. Just loaded 400 without a single primer issue. This thread was good at listing all the possible causes, thanks again! Oh, I also loosened the shell plate again, which wasn't even sticking.

I'm glad to hear you got it resolved.
 
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