First time shoulder bumper

[cowboy]

fj40mojo: You make a lot of sense and I agree with your comments.

Take a look at another solution that you may want to consider.

Competition Shellholder Sets | Redding Reloading Equipment: reloading equipment for rifles, handguns, pistols, revolvers and SAECO bullet casting equipment

For 40 years I thought that the best thing for accuracy was to neck size and then FL resize when the need arose. The last few years a new thought pattern has developed for the hunting reloader and that is to bump your shoulder back every time .001-.002.

My son was at the SHOT show and had the opportunity to spend quite some time in discussing this issue with various companies and he says he's wanting to try bumping the shoulder every time.

The above redding shell holder kit should be very simple to accomplish that.

If anyone has any experience using variable shell holders to accomplish this I'd be all ears.

 

[Nobody]

Let me ask you guys another question.

When I got the rifle, the gunsmith who built it told me that the cases should be resized to the extent that when chambering a resized case, the bolt should very very easily drop into the stock cutout. To do this, he told me I'd probably have to shoulder bump.

Does this sound...sensible?

 

[diriel]

sounds like the chamber is just a little too tight honestly. That is, headspaced short.

Good Shooting,
Gary

 

[fj40mojo]

fj40mojo: You make a lot of sense and I agree with your comments.

Take a look at another solution that you may want to consider.

Competition Shellholder Sets | Redding Reloading Equipment: reloading equipment for rifles, handguns, pistols, revolvers and SAECO bullet casting equipment

Interesting solution, I've always full length sized and have always followed mfg's instructions for setting my sizing die to accomplish this. That is until this year when I experienced some premature case failures, burned a lot of powder and wasted a lot of bullets in a custom 6.5x55 Swede I had built. After borrowing a set of headspace gauges and confirming my smith's claim that he had cut the chamber "tight", I bought the Hornady LNL headspace bushings and discovered that with my sizer set to mfg's specs it bumped shoulders back .014", double the allowed headspace per SAAMI spec. I will allways use this tool now and set my dies to bump .002". I use to be a machinist and you'd think that I'd know better but I'd been loading for many years and had never had a problem (until now) with this practice.

I considered necksizing for while, but after a discussion with a knowledgable friend he convinced me that a full length size with shoulder bump is the way to go. Neck sizing is OK for the bench rest guy where reliable feeding is not imperitive, but not for a hunting rig. A .002" bump only allows for .001" per side when the round is chambered, not a lot of room, but enough to guarantee reliable feeding while not leaving excessive headspace or misallignment of the projectile with the bore.

Nobody, a method to check your chamber to get an idea whether it is tight or not. You'll need a set go/nogo chamber gauges and a micrometer, rentable or borrow from friend or smith. Obviously you're go gauge should chamber easily, if not your chamber is too tight. You're nogo gauge may chamber or not, there is a misconception here because there is a third gauge the "Field" gauge which is the true high end of the allowed tollerance. If the nogo chambers your chamber may still be OK if a Field gauge won't chamber, your rifle will just be hard on brass loaded to factory specs. If you set your die to bump .002" on a Field gauge chamber it won't be any harder on brass than any other rifle. If it doesn't chamber the nogo gauge, your chamber is cut within standard tolerance. Now, you can find out exactly where your chamber is by shimming the back of the go gauge with scotch tape(.0015"-.002" per layer but measure with your mic) or .001 shim stock until it won't chamber, count the total number of shims and multiply by the thickness of your shim stock and add this number to the number etched on the side of your go gauge and the result is your chamber length from bolt face to datum point. My tight chambered 6.5x55 Swede will close on the go gauge with 1 shim but not 2.

 

[Gene]

Some good points, mojo. Setting a shoulder back .014" could be DANGEROUS. I would never fire that case, it is not worth saving. Nobody says he is able to bump shoulders just .001". That is about what I try to do when I bump. In this case, less is better. If you insert a case and the bolt turns down hard, the shoulder needs to be bumped ever so slightly. That is because the brass shoulder is bearing hard against the barrel chamber shoulder area. If your bolt handle nearly falls down with little pressure, you may have bumped too far. The go-no go guages will tell the tale. Yes, if the chamber is cut slightly too tight, a smith can run the reamer in again and cut it in just a bit more.

My usual practice is to neck size until the bolt turns down hard. Then I know its time to bump. I use the Redding Instant Indicator to measure bump, but any similar tool will do. When turning down the bolt handle to test case fit, its best if you can remove the cocking piece/firing pin assembly from the bolt. This will really tell the story. You can then actually feel the shoulder make contact with the chamber and you will instantly know whether its time to bump.

 

[captain cox]

i have had this problem before. i simply backed it off a bit. i would take a new piece of brass everytime you adjust the die. do half turn incriments and just cycle them in your rifle. you will find the sweet spot. you will be able to tell if you are getting closer or farther away by the feel of the bolt.