Shoulder Bump Range... What's Acceptable??

[Full Curl]

I tune all my guns the same way. What I end having to do with each to achieve my requirements are most often different. I wish that was not the case. No such thing as a cookie cutter approach to it. As the op didn't actually say what his overall goal was for his field guns, I can only guess he wanted some degree of improvement. I hope all the info here helps.

I just want to use the best loading process I can (within reason) to achieve the best accuracy I can from every rifle I shoot. The within reason parameters are what each of us determine for ourselves. This particular 300rum is a 3/4 MOA rifle on a good day and that is acceptable to me for field (hunting) use. I don't need a 1/4 MOA rifle, but if I can improve consistency of my current 3/4 MOA setup or even tighten it up a little bit without incorporating additional steps in my loading process, I will gladly take it!

From the sounds of it so far, it sounds like case lube application process, ensuring sufficient die dwell time, and annealing more often would be the most straight forward steps in my loading process that I can focus on improving and see if it leads to better/more consistent accuracy results.

 

[C-130 Dude]

I always try to get the best results I can when loading even for field shooting use... hence, why I would like a consistent .002" bump. I can certainly incorporate annealing after every firing if necessary but I still have not been able to get a perfectly consistent .002" bump on freshly annealed cases. I also do the 3 second press arm down stroke as you mentioned to reduce spring back. Thanks for the .001 to .003 acceptable range that gives me a good idea to compare my results to. And yes, brass, especially for a 300rum is expensive!

Please understand that the .001-.003 range is what I measured for MY guns. Yours may be different.

 

[C-130 Dude]

I just want to use the best loading process I can (within reason) to achieve the best accuracy I can from every rifle I shoot. The within reason parameters are what each of us determine for ourselves. This particular 300rum is a 3/4 MOA rifle on a good day and that is acceptable to me for field (hunting) use. I don't need a 1/4 MOA rifle, but if I can improve consistency of my current 3/4 MOA setup or even tighten it up a little bit without incorporating additional steps in my loading process, I will gladly take it!

From the sounds of it so far, it sounds like case lube application process, ensuring sufficient die dwell time, and annealing more often would be the most straight forward steps in my loading process that I can focus on improving and see it leads to better/more consistent accuracy results.

I think your on track. Hope your quest proves out.

 

[Full Curl]

Please understand that the .001-.003 range is what I measured for MY guns. Yours may be different.

10-4. Makes sense. I'll shoot a few of the .004" to .005" bumped cases and see what MY rifle tells me. At worst, they can be my future foulers. Out of the 100 cases I sized, only about 15 fall into this range meaning that the other 85 are in the .001" to .003/.0035" range.

 

[Full Curl]

I think your on track. Hope your quest proves out.

Hope so. Thank you for all the information and responses to the post. It sure gives me a lot to think about... I can already feel that rabbit pulling on my leg trying to tease me down his hole some more!!!

 

[L.Sherm]

10-4. Makes sense. I'll shoot a few of the .004" to .005" bumped cases and see what MY rifle tells me. At worst, they can be my future foulers. Out of the 100 cases I sized, only about 15 fall into this range meaning that the other 85 are in the .001" to .003/.0035" range.

I could have missed it but I would check your bump with the Wheeler method if your not

 

[milo-2]

I didn't bump the cases when they were new for the 1st firing. I did bump them .002" (goal) for the 2nd and 3rd firing and now again for the 4th.

I have my maximum case size shoulder measurement 2.4680" and bump back .002" from there.

Like I said, after 3 firings, and now reading this, all your brass should be very close to uniform after firing.
My tip, fire new brass as you did, on the first firing, with the case deprimed, find 7-8 longest cases, these are ones that need the .002" bump, get your die set for these, then run all your brass through, you will be fine for the 2nd firing.
On the next trip through the sizer is when I will finally set my die for this chamber for good.

Once again, your die is set for a .005" bump, or you wouldn't be getting that much on a few cases. I am not a fan of Imperial lube, as I never seem to get a uniform lube unless I dip my fingers every case, doing so puts too much lube in the die, and on a RUM case, may result in hydraulic dents. I use one shot, or homemade lube, spray, let the cases sit for a day at least, go to work. No lube is needed on the necks or shoulder area, just the bottom half of the case body, I tip my cases upside down to spray them.
Per your post #43, a uniform bump now will not transform your 3/4" rifle into a 1/4" one, lot of factors playing here.

 

[L.Sherm]

im not leaving anything on the table so to speak.

To the best of my abilities anyway

 

[terry 338rum]

if the brass was all fired in the same chamber you should do what KEC said, I have 338 RUM with atlas brass and follow this procedure and do not have any problem with the cases being more than 1or .ooo2 different and i shoot very small groups.

 

[Philward]

Whidden makes a 'click' die that allows you to move the die in .001" increments without loosening the lock ring. The 'click' is built into the ring and the threading on the die body had detents in it.

I wonder if this similar to the EC dies. Just watched his intro video of them, micrometer adjustable. EC= Eric Cortina. Maybe it's just micro adjustment of the lock ring... but he tightens the set screws down on the lock ring and then adjusted the shoulder bump.

 

[C-130 Dude]

Whidden makes a 'click' die that allows you to move the die in .001" increments without loosening the lock ring. The 'click' is built into the ring and the threading on the die body had detents in it.

I've been using them for over 2 years now. Works great. I also use them on my Giraud trimmer. Oh so easy!

 

[L.Sherm]

. I also use them on my Giraud trimmer. Oh so easy!

I've been trying to convince myself I NEED one of these. LOL

 

[C-130 Dude]

I've been trying to convince myself I NEED one of these. LOL

It took a bit for me to figure out how to adjust them, but afterward, I find them a huge time saver. Adjusting dies never gave me confidence that I got it right. Too much hit and miss. These click dies work great. BTW, if you get one, do not tighten the lock screw to much. Its not necessary. The instructions state this. Read it through well. Pay attention. Last time I bought them, they were $50.00

 

[L.Sherm]

I've got 2 of Johns click dies and i think 4 or 5 of his before the click came around its the Giraud I'm trying to talk myself itnto, should have made myself more clear