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I bought a Weatherby Vanguard in 6.5 PRC. I shot it today trying to zero the scope. I had loaded some new Hornady brass with a 129 grain SST and 60.0 grains of Magpro powder, which is a couple of grains below max. The first shots all extracted perfectly and showed no signs whatsoever of pressure. The next several rounds I fired all required me to slap the bold handle hard in order to eject the fired case. There was no sign of the pressure in these cases either. I've never experienced a situation such as this, where cases stick with no signs of pressure. If there was something wrong with the chamber on the rifle, it seems to me that every case would stick, rather than just part of them. Any ideas as to what's wrong.

Accordingly to Hornady loading manual 60 grains of Magpro may be max. You should start with 55.5 grains as starting load. Not sure what pressures signs you expect, but you must begin with starting load and work u carefully. Internal pressures can be exceeded with no outward signs. Your starting load was too high. Hard extraction is a sign of high pressures.

Yes sir, high pressure, I always start few grains under max and work up.

Cases sticking in a chamber actually is a pretty good sign of pressure

While I always thought so, the cases that aren't sticking require absolutely no effort to eject. The bolt opens with no resistance whatsoever on those. The primer looks perfect on the cases that stick, showing no signs of high pressure as I've seen in other cases. I'm going to try some different powder and see what happens, but I am not convinced the loads are too hot.....at least not yet.

You might want to get your 0-1 mics out and measure the case head about .200 up from the head
Compare unfired against the ones that stick.
Case head expansion is a good indicator of high pressure

dave

In addition to possible high pressure there is the issue of "clickers" with 6.5 PRC brass. The last motion of the bolt handle upwards is difficult and results in a click when finally open.

This thread is worth reading.

https://www.longrangehunting.com/threads/the-prc-die-problem.253223/

The brass is thick and relatively hard at the case head. One would think a small base die would solve the issue, which it doesn't. The proper solution is a slightly larger reamer dimension for the case head area. An alternative is to sand and polish the region.

I know, I have two 338 RCMs that had the same issue. The RCM is the parent case for the 6.5 PRC. I had SAMMI spec reamer and three different sets of dies including Whidden which were made based on my fired cases. None worked still had clickers. Made a small base die by cutting off the top and bottom of a RCBS FL die to make a sizer for the base. It helped some but the final solution was to sand and polish the rear of the chamber. The author of the thread, Alex Wheeler, has designed a reamer with different dimensions which is the proper way to solve the problem.

Similar issues can occur with WSMs, RUMs, and SAUMs.

Az, a problem with the brass was the first thing that came to mind. The bolt handle lifts with ease, but takes a hard push with the hand to come back. As I said, it doesn’t do it every time, which should be the case if it was a pressure problem.

At any rate, I’m going to try a few different things and see what happens

Actually, according to several tests I've run in pressure labs over the years, sticky cases are the most consistent indicator of high pressure, more so than primer appearance or even ejector-hole marks on the case head.

Of course, higher than expected muzzle velocities are also a sign of high pressure, but an amazing number of handloaders still don't use a chronograph--or if they do, somehow think that "extra" velocity is due to the special characteristics of their particular rifle.

Got one for you MD

223 load 25.5 grains Benchmark, 7 1/2BR primer and Speer 52 match 10 shots each, Oehler 35P

Norma commercial brass 3417
Nosler 3396
Norma 556 unturned necks 3389
Norma 556 with necks turned 3378

Each and everyone of the 556 brass gave me what’s described as clickers on firing and extraction. Accuracy is on par with the commercial which gave 0 clickers after firing and slightly higher velocities.

Your opinions on cause of the clickers, since it happened on turned necks thinking it’s the thickness of the base or might need a small base die?

Oversized firing pin hole.

Doubt that completely as it’s bushed.

How fast were your loads showing on the chronograph?

JamesJr,

I thought the slap was upwards. Later on in another of your posts you say the issue is moving the bolt rearward after the bolt is lifted. Again it could be pressure.

Look carefully at the extracted case. Does it have shiny marks or scratches on the body? A chamber with a low spot causes the brass to form into it which makes rearward removal difficult, just like excessive pressure, but the tell tale body marks are present.

I should've added: "Unless it's already bushed".

Sounds to me like base interference. I've had some success correcting this by additional sizing of the base.

Thanks Jordan.

Check to see how much primary extraction the action has before going much further.

Good shootin' -Al

And also how rough the camming surfaces are. Have solved a few hard-extraction problems by smoothing those surfaces, and lightly oiling or greasing them.

Good call, Al. That would be my first suspect, too.