16ga.com ~ View topic

Joined: 21 May 2015 Posts: 128

Anyone yet checked out the data?

I have and need a sanity check.

I filtered for:
• Chedite (I assume 2-3/4, 6pt crimp)
• 1 oz
• Universal powder
• Ched 209 primer
• BPI SG 16 wads

There seems to be an interesting anomaly with the Polywad spreader…. Hodgdon data powder charges less than, equal and well above show 1kpsi lower.

Joined: 04 Mar 2019 Posts: 1844 Location: Central ND

You lost me, what load are you loading (or looking to load) and what load did Hodgdon publish?

And. before you take this too far and get all twisted up....the loading data was produced by lots of different folks and some of the loads were really not tested the way they should have been (using only 2 or 3 rounds in some cases) and who knows how well the reloads were even loaded. There are lots of variables at play.

Not saying that the reloading sheets are inaccurate, but I am saying there are lots of variables.

Joined: 21 May 2015 Posts: 128

MSM,

Not even near "twisted" up on this. I was just looking as I stated for a sanity check.

For the parameters I listed and charges of 20.5 thru 23.0 gr Hodgdon publishes pressures of 7500 to 9200 psig respectively. The LPG load of 20.5gr is 9400 psig.

Joined: 28 Aug 2014 Posts: 924 Location: Eastern Tennessee

Not sure if you’re using my compiled list, however, as previously pointed out it isn’t uncommon for someone to take a factory provided recipe and have it test only to find a distinct variation from the list data. This is due to an inability to eliminate numerous variables. My goal was not to ascertain the accuracy of tested results, but only offer the existence of them and when a known variation was also tested that this data was also present for your further scrutiny.

I myself am very hesitant to use BPI provided data due to my own concerns about their practice. I will also say that just because the have a recipe doesn’t mean the combination is ideal. When I see ball powders in straight walled hulls using Remington wads I quickly shake my head. These ingredients don’t really go together in any sort of ideal way.

Joined: 04 Mar 2019 Posts: 1844 Location: Central ND

I have some similar data using Winchester 209's in Cheddite hulls with the rest of the components the same as you posted and it falls somewhere in between the two sources you mentioned.

I didn't mean to be rude, but basically this is a chase your tail exercise. Two different sources of the actual reloads and different labs doing the testing. Too many variables to make it an apples to apples comparison.

Pick the load you like and have fun with it. If you have a chronograph, you can narrow it down a bit.

If you look at the progression of Hodgdon's loads 2.5 grains top to bottom 1,700 PSI spread and a 110 FPS spread is right on the money as far as rules of thumb go.

Figure 800 to 1,000 PSI, and a 50 FPS increase for every 1.0 grain of powder increase using Universal.

My data is exactly 2,000 PSI increase on pressure for a 2.0 grain increase but my velocity went up 75 FPS with each 1.0 grain increase. However I probably have a deeper crimp than most at .065" rather than the standard .055" crimp depth. Not sure how the Winchester primer affects things either.

This is how you have to look at published pressures and velocities. On the day that the loads were tested this is what the technicians got.

I have seen in house reference loads that I loaded vary 500 PSI and 20 FPS from day to day. Sometimes it hit the original averages and sometimes it didn't. You have to roll with it. After you test a few thousand rounds of ammo you get used to it.

We have gotten used to things being exact or seemingly exact in the digital world. Nothing about a shotshell is exact.

to add a little to Mark . When you send loads to Precision for instance , they note the temp and atmosphere on the report . You'd probably have to look at a million (i know!) data pts of the same load to get (maybe ) an avg !!

Joined: 21 May 2015 Posts: 128

MSM, 16ga,

Your comments beg the question on how consistent we reload.

When I start out I measure every drop, then every 5, then every 10 in sequence to check out the process.

On rolled crimps I measurer out every charge, because I interrupted the cycle.

And, I pick recipes for forgiveness sometimes. My 20 ga. go to with 20/28 is about the same pressure over 2 gr.

I take care to tune my crimps too. They usually look better than factory...

All of this to chase a safe, repeatable load.

Joined: 04 Mar 2019 Posts: 1844 Location: Central ND

I really don't know that answer.

If I am trying a new target load, I reload 5 weighing powder and shot and send it over the chronograph. Then I usually take at least 5 rounds right off my 9000 after it is setup the way I want. I probably reload at least 25 rounds and then take 5 rounds off the machine and send them over the chronograph. Most times nothing really changes.

Recently I was messing around with some 1 oz. loads using 572 in RGL hulls. The hulls were all once fired but there were two different lengths and it was messing with the crimp depth. Those loads were not horrible but they weren't stellar either. There was about 20 FPS between the 2 hull lengths and when you mixed the two hull lengths together and shot them it showed up in the SD and EV numbers.

This is the kind of thing that can happen and if I hadn't used the chronograph I wouldn't have paid a lot of attention to it.

I believe that powder and shot drops on most progressive machines using most powders are reasonably consistent. Not too sure about powder drops on single stage machines.

There are just so many variables that can be introduced I really don't look at velocity and pressure numbers as absolutes, but more like good guidelines.

I say that, but generally whatever velocity is published, I am within 10 - 20 FPS of what is published on any load I have ever chrono'd.

To get back to your question, I believe it is up to each person doing the reloading as to whether the reloads are consistent or not.

Joined: 21 Mar 2019 Posts: 45

I would have to check to be sure but that looks very similar to a load I’ve shot a bunch of except…WW primer instead of Cheddite. Very good load at any rate.

John