Hard Bolt Lift

[Kurt Blasser]

I have a Straight 284 Win F Open rifle that I have been shooting necked up Lapua brass, Win 284 brass and Norma 284 brass without problems. Got a batch of the new Peterson 284 brass and loaded a ladder with 4831 SC powder, Berger 180 Hybrids and 184 Hybrids. Starting charge was 51 grains going to 55. New brass, sized .002 less than the prior fired brass mentioned above. Trimmed, necked to .014-.015 for a .317 chamber. Neck tension .0015-.002. Shot up to 54.6 without any signs on the brass of being to hot, but every round had very hard bolt lift at the very end of the lift. No problems with the early part of bolt lift that I have seen when load to hot. Never had problems with the other brass above. Measured a load of lapua brass fired same tim and shoulder measured 1.807, fired Peterson 1.807. Measured remaining loads, set back on lapua 1.799, on Peterson new brass set back to 1.801. Lapua base of case measured .499 as did Peterson. Any ideas or suggestions?

 

[gman47564]

that's a tough one... are they both trimmed to the same length ?

 

[Kurt Blasser]

You may be on to something. Just did a lot of measuring. The neck thickness between the brass that ejects fine is .014 and that of the Peterson .015. The trim to length in the Sierra Manual is 2.160 and that's what the Peterson brass was trimmed to. The Lapua that I fired is 2.150 and had no ejection issues. There wasn't any chambering issues with either length.

 

[Kurt Blasser]

Nope, Trimmed the fired cases to 2.150 and still hard to eject, lift terminal bolt.

 

[JFrank]

Nope, Trimmed the fired cases to 2.150 and still hard to eject, lift terminal bolt.

Are you familiar with a slotted Sheridan gauge

 

[JFrank]

www.sheridanengineering.com

 

[F Class John]

@SPJ ^ Yeah a good slotted gauge is great to have for lots of uses. My gunsmith makes one out of old barrel anytime I get a new chamber done since my reamers are custom. I don’t use it everyday but boy it’s great to have when you need it.

 

[Ccrider]

I would recheck my base and shoulder measurements again. It has never failed that when I get bolt click my problem is with the base of the case.

 

[Sandstorm]

Im thinkin your on to somethin ( Ccrider )
Ive been experiencing that same issue on and off with my 6.5x47 Lapua..Thought it had to do with a really tight chamber dim
on my rifle...but perhaps its in the die. ( pardon the thread hijack )

 

[Ccrider]

I did not come up with this. I am just repeating what I have learned through experience and being told what to look for by the helpful experts on this site.

If you are having tight bolt close, you likely need to bump your shoulder back. Some will tell you .001 to .0015. That may work but a lots has to do with where you are measuring on your shoulder.

Bolt click on open is usually caused by expansion of the base. The correct full length sizing die will fix both and minimally work your brass.

 

[gman47564]

I thought there could have been some carbon built up in the chamber but if their still doing it after trimming them then must be something else.. i would still give the chamber a good cleaning if you havnt already just to rule that out..

 

[Sandstorm]

Thanks for that..Ccrider.. Its a Whidden die and im fixin to send him the die back with some fired cases for a massage.

 

[Kurt Blasser]

Not familiar with the Sheridan Gauge and they don't seem to have a 284 on the web site. I've taken some video I'll include. No problems chambering the Peterson brass. I've measured everything two three times on 10-12 cases. Only after fired. Maybe case base too tight? Need small base die? Whidden click adjustable full length sizing die being used now. Has anyone else had to go to a small base die with the Peterson brass?

 

[gman47564]

Measured a load of lapua brass fired same tim and shoulder measured 1.807, fired Peterson 1.807. Measured remaining loads, set back on lapua 1.799, on Peterson new brass set back to 1.801

am I reading this right... are you saying the shoulder is set back to 1.801 and a fired case measures 1.807... if I am your pushing that shoulder back way to far and will end up with case head separation in short order.... a couple thousandths shoulder bump is a plenty.. and with that much play in headspace your cases may be slamming back against the bolt face swelling the case just above the rim..

 

[Kurt Blasser]

Video

 

[Kurt Blasser]

Measured a load of lapua brass fired same tim and shoulder measured 1.807, fired Peterson 1.807. Measured remaining loads, set back on lapua 1.799, on Peterson new brass set back to 1.801

am I reading this right... are you saying the shoulder is set back to 1.801 and a fired case measures 1.807... if I am your pushing that shoulder back way to far and will end up with case head separation in short order.... a couple thousandths shoulder bump is a plenty.. and with that much play in headspace your cases may be slamming back against the bolt face swelling the case just above the rim..

Sorry, Fired Lapua and Fired Win and Fired Norma and Fired Peterson all measure 1.806-1.807.
New Peterson is 1.799-1.801 in box. Bumping the others to 1.804-805.
Fired case just above rim is .499 on both Lapua and Peterson.

 

[JFrank]

I’ve added this direction to measuring, just not to miss anything.
So I’m reading your bump at .002 so personally I size to just enough to chamber freely or about .003

 

[savageshooter86]

Measure at the 200 line on the Peterson brass. Might need a small base sizing die

 

[Jet]

The third video shows clickers. You will need a die to size the base of the brass more. I'm sure Whidden can take care of that for you.

 

[Kurt Blasser]

Chambering was not an issue. When I refer to the .499 I'm trying to measure the case head area, and they all measure the same.

Measure at the 200 line on the Peterson brass. Might need a small base sizing die

Where is the 200 line?