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125gr RN Blue Bullets data


Slattin
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So I just got package of blue bullets 9mm 125gr RN. I was looking at hodgdon site for some general load data using HP-38 for plinking loads. Hodgdon data shows for FMJ 4.4-4.8gr and a OAL of 1.090. I know the length varies based on the gun you are shooting, I can adjust that. Is that powder min/max correct even though I'm using PC and not FMJ? I normally like to stay in the middle to account for powder drop variances. Is this correct in my assumption?

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13 minutes ago, Slattin said:

So would LCN be similar to coated RN from a data prospective?

 

Similar, but not exactly.  LCN means, "Lead, Conical Nose".  

 

Using data for the 125 grain LCN load data will work pretty well with your 125 grain Coated RN Blue Bullets. 

 

I have loaded 4.4 grains of HP-38 under another brand of 125 grain coated bullets, without issue.  

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The charge under a lead conical and RN will be about the same when looking for your starting point. 

However, OAL might be different based on you plunking your barrel.

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My advice is that if you never loaded these bullets before, never had a similar load for this particular pistol, and maybe not seasoned with this loading type, I would start at about 10% below the minimum. Make sure to the "plunk" test with your barrel for the OAL so there are no surprises and take it slow. This situations sounds like too many unknowns so I would be cautious and double check everything before taking the load to the range. Make sure your chrono then verifies your data. This along with the above suggestions and you will be fine. Good luck with the new load! Let us know how it goes please.

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Have you ever loaded a coated 124/125 with that powder before? If yes, I'd load that same load with maybe a tenth or two less powder, and chrono from there. If no, start at the min data as always. If your OAL is significantly longer than the book data you're using, you might need a hair more powder for the same velocity.

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17 hours ago, BJB said:

The charge under a lead conical and RN will be about the same when looking for your starting point. 

However, OAL might be different based on you plunking your barrel.

 

16 hours ago, BJB said:

OAL listed in manuals is not a must for you & your load.  Your OAL may differ based on your barrel leade and your bullet profile, etc.

 

I agree. And if your velocities magically equaled Hodgdons, the load to get 130 PF would be around 4.2 grs. vs the 4.4 Hodgdon shows as Max. Finding the correct OACL for YOUR barrel is the greater challenge here. As far as the data being for a 125 gr. LCN, look at your RN and compare it to the BBs 125 gr. coated TC and it appears that the shank is just a tad longer for your RN. That means a slight difference in bearing surface with the bullet of greater bearing surface giving slightly higher pressure. The difference is slight in this case, and given that Hodgdon's Max Charge of 4.4 grs. shows pressure at 31,200 CUP, there is a safety cushion there and even more if the charge req'd did turn out to be 4.2 grs.

 

It's easier done with a jacketed bullet of .355" dia. But with a coated bullet at .356" you're gonna need to use your press to develop your own OACL. Using small adjustments, shorten the load in increments to the point that the rim starts getting close to being flush with the barrel's hood. Then shorten in smaller increments like .005" until the case rim is just below the hood. This may or may not result in the exact OACL with your adjustments being made in .005" increments, but it will get you very close. If the load at that point will plunk and spin, shorten by at least another .005" or even .010" for a safety cushion to know that your bullets will not be touching the barrel's leade. There will be some variation in OACL, and Ideally it's best for the longest of your loads to still be at least .005" from touching the leade. This is referred to as Free-Bore.😉

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Some of you are overcomplicating the matter. Powder does not care about the shape of your bullet (wadcutter being the obvious exception). Only bullet material and weight matter. Use lead data for lead and coated lead, use FMJ data for plated and FMJ. Only your barrel cares about the shape of the bullet so make sure you plunk and spin.

Edited by 4n2t0
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1 hour ago, 4n2t0 said:

Some of you are overcomplicating the matter. Powder does not care about the shape of your bullet (wadcutter being the obvious exception). Only bullet material and weight matter. Use lead data for lead and coated lead, use FMJ data for plated and FMJ. Only your Barrel cares about the shape of the bullet so make sure you plunk and spin.

 

That's not really accurate. Bullet shape and OAL effect the case volume which will effect the pressure. 

 

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59 minutes ago, Racinready300ex said:

 

That's not really accurate. Bullet shape and OAL effect the case volume which will effect the pressure. 

 

 

Have you ever witnessed a published load become unsafe because of the OAL? 

 

My advice to the OP......K.I.S.S.

 

Edited by 4n2t0
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1 hour ago, 4n2t0 said:

 

Have you ever witnessed a published load become unsafe because of the OAL? 

 

My advice to the OP......K.I.S.S.

 

 

I haven't looked at published loads in years. I'm all for keeping thing simple, I don't chase the perfect load I find something that works and load a lot of it. But, ignoring part of the equation seems silly to me.

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1 hour ago, Racinready300ex said:

 

I haven't looked at published loads in years. I'm all for keeping thing simple, I don't chase the perfect load I find something that works and load a lot of it. But, ignoring part of the equation seems silly to me.

 

So that's a big fat no, got it.

 

I would love to see all the pressure data you've collected over the years by not "ignoring part of the equation" 🙄.

Edited by 4n2t0
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4 hours ago, 4n2t0 said:

Some of you are overcomplicating the matter. Powder does not care about the shape of your bullet (wadcutter being the obvious exception). Only bullet material and weight matter. Use lead data for lead and coated lead, use FMJ data for plated and FMJ. Only your barrel cares about the shape of the bullet so make sure you plunk and spin.

 

All bullets at a specific weight do not share the same shank length/bearing surface. Differences can be slight enough to be moot with little or no effect on the powder charge, but a different example would be a RN compared to a SWC. With the same bullet construction and diameter, length of the bearing surface can effect pressure/velocity.

 

A wadcutter as you mentioned is an exception because of the longer shank/greater bearing surface and typically made for revolver calibers.😉

Edited by K-Texas
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1 hour ago, 4n2t0 said:

 

So that's a big fat no, got it.

 

I would love to see all the pressure data you've collected over the years by not "ignoring part of the equation" 🙄.

 

I assume you have all the data you've collected showing pressure isn't effected buy different length bullets?

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