Extreme Spread Inconsistency - Infrequent but it happens

[338winmag]

16 out of 20 rounds with minimal ES of around 4-13 FPS.
3 or 4 of them will be greater and often 35-50 FPS
This ES opens up what would be perfect 1/2" - 5/8" groups.

Using Lee Collet Die and applying .0035 tension using the cam over feature on a Rock Chucker.
Measuring powder to a perfection like my life is depending on it.
Every single bullet's seating depth is measured with a digital gauge

I am not culling the brass or the bullets. Could this make a difference or is the Lee Collet die approach maybe part of a problem?

This is happening with any caliber I am reloading. There is always 3-4 or even 5 out of 20 that have high velocity deviation no matter how careful the reloading.

Thanks
338winmag

 

[rick smith]

Is all the brass the same lot? Has the brass been fired the same number of times? How many times has the brass been fired? Are you FL sizing every time since you mentioned camming over? You may be overworking the brass.Rick.

 

[338winmag]

Good Questions.
Brass is all same manufacturer and lot.
All shot 2 times
With the collet neck sizing die I am using a rock chucker press and just allowing a slight resistance to cam over (I have not FL sized the brass yet.)

 

[Desert Fox]

I am not culling the brass or the bullets. Could this make a difference or is the Lee Collet die approach maybe part of a problem?

I think you just answered your question.

 

[rick smith]

If this is happening with any caliber you load, you have a Gremlin on your bench. Which round in the sequence does this? Is the rifle bedded? Won't change the velocity difference but it would explain fliers. I would try a fresh batch of primers/powder.
Do you get the same if the brass is new?
Tried various seating depths?
Any other tensions on the neck?
Different bullets/powders?
I don't use the Lee Collet die so can't offer sugggestion but wonder why you have to cam over.Rick.

 

[338winmag]

I wouldn't be surprised if there is a gremlin. Actually on the 7mm Rem Mag, pretty consistent. All others, yup.

I am culling brass and bullets right now as we speak. (For 3006 and for 300 WM) Will advise in the next day or so if this makes a dfference.

With the rock chucker, there are two ways to approach.
1. Set die to shell holder deep so that you do not complete the lever stroke. Problem is you kinda guess how much pressure you are placing on the handle.
2. If you set according to manufacturer specs, the rock chucker will cam over slightly. Manufacturer does not recommend but myself and others have found setting it slightly to cam over seems to give it a "consistent pressure" for each case.

Thanks all
Steve

 

[Oldtrader3]

The die manufacturers (at least Forster) have always recommended over camming the dies a little on sizing. Most dies will produce a properly headspaced case for most chambers with a slight over cammed press stroke. Of course you need to measure shoulder setback (headspace) as this is the most important attribute of consistant loads.

 

[rick smith]

338, are you weight sorting or sorting by neck thickness? Both can make a difference.

Old, I set my FL dies to PFL the cases after they get snug from neck sizing, measure to the datum line and set to bump the shoulder 1-2 thousants. Setting to cam over without measuring can cause headspace problems and casehead seperation.Rick.

 

[338winmag]

So I went out Sunday performing all the new suggestions. I definitely know that I will incorporate 2 shots only and then switch to another rifle. This has worked very well.... but...... the ES was still there no matter what.

I broke a few rounds down to reload and decided to test the powder weights. :shock: :shock: I found 2 out of 9 to be off +.2 and +.3. How can that be with me measuring each throw 2-3 times???

I started writing a book on this but bottom line... I found that if I place the pan so softly that the upswing barely travels past the middle mark, the powder weight will be off +.1 to +.3. OMG!!! I can repeat the findings now pretty often. I called RCBS and they were familiar with the issue and are sending me out something to replace the defective or worn parts. Forgot what they are for now.

Anyway after doing some research for new scales, I found some others with similar issues with that RCBS 5-0-5 scale. They purchased the RCBS Chargemaster 1500 digital scales and never looked back.. And guess what, their ES improved greatly.

I went out and got me one, reloaded some 30-06 and some 7mm Rem Mag and took off to the range. Guess what? The ES for the 30-06 was 20 or less with most around the SD of 9. The 7mm Rem Mag shot some with the same FPS and deviation was less than 11. No more 45-60 FPS. I was throwing an occasional heavier charge and not knowing it no matter how much I was triple checking my throws.

BTW - this RCBS Chargemaster 1500 is so fast, smooth, Consistently ACCURATE and too easy. From here on out, the beam scale is when the power is out and for validating the digital scales only.

Thanks all
338winmag

 

[SJB358]

Man, this is going to make me wanna try one of those new scales as well! Scotty

 

[338winmag]

I hate to say it.... but the cost almost made me not buy it, but others stated the same thing and were happy once they spent the money for both the scales and the dispenser.

Now, I am the same way 100%. Geeesh, I hate to spend a lot of money when I can do it another way (my wife's says I am cheap - I say I am frugal), but once i got started with multiple calibers and different reloads... its not just easy, its not just efficient, it was so quick as to allow me to bullet seat, measure every round on the digital headspace gauge, which you now have scotty, and it is so dog gone accurate I stopped thinking about the money.

It is sensitive to bumping the table or desk in that it will drop a powder granule or two but if I see it go over .1 or .2, I just remove the pan and pinch one or two granules out of the pan and reweigh. Tada. Also I noticed the sc version of 4831 is smaller granules so it can sometimes spin one or two granules more than you want. Again just remove pan and pince one or two granules out.

I know ES is not everything but it was definitely affecting my POI becuase of mismeasures. Now I will start "shooting" (a little pun there - lol), for single digit S.D.s.

I am just crossing my fingers that it lasts a year without issues. After that RCBS will repair or give you a new one for $45.00. And the 1 year warranty starts all over again.

Pretty cool

 

[SJB358]

Man, I may have to talk the wife into getting me one. I have wanted one for quite awhile. Scotty