Baldrage's reloading log

[Wobbly]

I will, however, look into whether the plastic [ball] bearing sold for the 650 would work on the SDB.

https://ballistictools.com/store/dillon-press-enhancements

Ebay auction #321239314109   [has a great explanation]

http://hitfactorshooting.com/

...or McMaster-Carr industrial supply http://www.mcmaster.com/#standard-plastic-balls/=14gtf0j

[painter]

How about a lighter spring under the steel ball so it slides into position instead of being rammed into position?

We tune our pistol springs for suitability.

[Wobbly]

Call Wolff Spring and see if they stock one for the Dillon SDB !!

 

[IDescribe]

There was a guy at 1911Forum.com who bought a 650 and then spent a lot of time going back and forth with very receptive techs at Dillon, improving this and that function of the 650, updating the press periodically throughout the process.  It was a super informative thread, and I believe the guy knew his stuff.  His solution was a nylon/plastic/polymer detent ball.  The lower mass meant that there was less energy to deliver through the shellplate, AND the fact that the ball would give way and compress a little at the moment of impact meant the strike and energy transfer was less sharp.  It makes sense to me.  I think of a Newton's cradle, and that polymer ball just makes more sense.

[painter]

I'm sure the plastic ball helps, but if the ball is solid I'd think the amount of energy transferred would be close to the same. I can do a fair amount of damage with a plastic, or rubber, hammer.

I don't think like an engineer, however, so I'm likely wrong. 

[baldrage]

I will, however, look into whether the plastic [ball] bearing sold for the 650 would work on the SDB.

https://ballistictools.com/store/dillon-press-enhancements

Ebay auction #321239314109   [has a great explanation]

http://hitfactorshooting.com/

...or McMaster-Carr industrial supply http://www.mcmaster.com/#standard-plastic-balls/=14gtf0j

Thanks for these links, Wobbly.  I have inquiries out to each of the companies to see if their detent balls/bearings will work with the SDB.

[baldrage]

OK, long weekend coming up, so hopefully I will have time to produce my first test run of loaded ammo.

Planning to start with the 124 gr RN FMJ bullets from Rocky Mountain Reloading.  Recall that based on results of ?plunk? test, I am planning to use OAL of 1.125 (max OAL of 1.140, and subtracting .015 for set-back puts me at 1.125).  I will be loading these with HP-38, and looking at Hodgdon Data Center, I see they have load data for 125 gr SIE FMJ, which is the closest thing I can find to my 124 gr RN FMJ from RMR.  They list OAL of 1.090, starting load of 4.4 gr, max load of 4.8 gr.  Since my bullet is 1 gr lighter, and my OAL is longer (1.125 vs. 1.090), I am safe to start at 4.4 gr and work up in .1 gr increments to 4.8 gr, correct?

[painter]

You would be safe with that procedure IMO. You might not make the listed velocity.

Keep in mind that with regard to pressure it's all about bullet weight and seating depth, not OAL

There's a thread a couple down that speaks to this because the 2 bullets in question are not the same length.

http://www.czfirearms.us/index.php?topic=83058.msg612211#msg612211

If your bullets are actually .2 longer, your seating depth will be .1 less at the oal you've chosen, and you'll be fine.

eta...

the 1 grain difference in bullet weight is inconsequential. You'll find close to that variance +/- in most bullets of the same weight from the same batch.

[IDescribe]

What Painter said.  PLUS...

Take off your shell plate and measure your detent ball.  I will measure mine at first opportunity.  If they match, anything specifically intended for the 650 will work.  If they do not match, use the company that sells an assortment of sizes and buy the matching size.

And are these actual FMJ?  I know RMR is selling jacketed rounds now, but they also sell plated RN, and sometimes new reloaders will call plated RN bullets FMJ, thinking they're the same thing.  Just wanted to verify that they're FMJ.  If so, as Painter said, that load data is fine.  It won't work out exactly, but starting load will cover you in terms of safety.

[baldrage]

Thanks as always for the responses!

Take off your shell plate and measure your detention ball.  I will measure mine at first opportunity.  If they match, anything specifically intended for the 650 will work.  If they do not match, use the company that sells an assortment of sizes and buy the matching size.

I measured it last night, it is .1875 inches for the SDB detent ball/bearing.

And are these actual FMJ?  I know RMR is selling jacketed rounds now, but they also sell plated RN, and sometimes new reloaders will call plated RN bullets FMJ, thinking they're the same thing.  Just wanted to verify that they're FMJ.  If so, as Painter said, that load data is fine.  It won't work out exactly, but starting load will cover you in terms of safety.

Thanks for asking.  I know from what I have read that there is a difference between plated and FMJ, and I specifically bought the FMJ from RMR.  That said, I'm not sure I could tell the difference just by looking at an actual bullet.     I will compare to some of the plated bullets I bought from X-treme and see if I can discern/verify a difference!

[Boris_LA]

That said, I'm not sure I could tell the difference just by looking at an actual bullet.

Plated bullet will have the base of the bullet covered and most FMJ will have an exposed lead on the bullets base.

[painter]

Just to add...a covered base in a FMJ is usually termed a TMJ or Total Metal Jacket.

You can tell for sure by poking at a bullet with something hard. A plated bullet will dent pretty easily. A FMJ is much more resistant.

[baldrage]

You would be safe with that procedure IMO. You might not make the listed velocity.

Keep in mind that with regard to pressure it's all about bullet weight and seating depth, not OAL

There's a thread a couple down that speaks to this because the 2 bullets in question are not the same length.

http://www.czfirearms.us/index.php?topic=83058.msg612211#msg612211

If your bullets are actually .2 longer, your seating depth will be .1 less at the oal you've chosen, and you'll be fine.

eta...

the 1 grain difference in bullet weight is inconsequential. You'll find close to that variance +/- in most bullets of the same weight from the same batch.

I read through the thread on seating depth ... to make sure I'm understanding this correctly ...

Seating Depth = Case Length + Bullet Length - OACL

So for my 124 gr RMR FMJ (.605), using Blazer Brass casing (.7440) and 1.125 OACL, my seating depth = .605+.7440-1.125 = .224.  By comparison, the Hodgdon load data for Sierra 125 gr FMJ (.575) doesn't have case length listed, so using same Blazer Brass case length for comparison (?) and 1.090 OACL, gives seating depth of .575+.7440-1.090 = .229, or .005 difference.  Is five thousandths of an inch difference in seating depth significant enough to warrant addressing, or should I just proceed with recommended starting loads and work up in .1 gr increments?

[Wobbly]

No, 0.005" is not going to effect your results one way or the other.

However, you only need something around 0.200" bullet seating depth to get the best results. A seating depth around 0.230" might rule out using certain brass. And, just because a load book writer used a certain OAL doesn't mean you have to; you can always go longer and err toward lower pressures.

Honestly, in your shoes (and I'm not, I promise) I might use 1.100 or 1.110". That's not going to change your incremental load ladder for testing or make you use more powder. It's simply going to back you away from issues with certain brands of brass and hopefully improve the feeding reliability.

[baldrage]

OK, Wobbly sir, now I am confused.  You stated:

And, just because a load book writer used a certain OAL doesn't mean you have to; you can always go longer and err toward lower pressures.

Yes, that was my understanding and my intent.  Hodgdon load data has 1.090 OAL.  Based on results of my plunk test and subtracting .015, I was planning on using 1.125 OAL.  So, longer, erring toward lower pressures. 

But then you say:

Honestly, in your shoes (and I'm not, I promise) I might use 1.100 or 1.110". That's not going to change your incremental load ladder for testing or make you use more powder. It's simply going to back you away from issues with certain brands of brass and hopefully improve the feeding reliability.

The RMR bullet I am using measures 0.605, the Sierra bullet used by Hodgdon is 0.575, so my bullet is about 0.030 inch longer.  However, the OAL I am using is 0.0305 inch longer (1.125 - 1.090).  So, am I correct in thinking that pressure caused by seating depth should not be an issue? Wouldn't reducing OAL from 1.125 to 1.100 or 1.110 as you suggest, closer to Hodgdon's 1.090 OAL, increase pressure (albeit just to a small degree), thereby reducing my "safety" margin?  Also, could you explain why this would improve feeding reliability?  My understanding was that as long as I was under SAAMI max of 1.169, and using an OAL that passed the plunk test in my barrel (and above minimum of 1.0), the round should feed reliably.

I know that is a lot of questions, but I thought I had a good handle on determining proper OAL based on reading the stickies and many previous threads in this forum.   Now you have me second-guessing myself, and I need to make sure I understand properly before proceeding any further.