Where to go from here?

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dellet
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Re: Where to go from here?

Post by dellet »

With the right search query, many things turn up.

Honestly this is a generational thing. Somewhere in the 80’s at the latest, kids in school were no longer taught how find information, only how to find answers. If you find information. You arrive at your own answers. Not saying the happens everywhere, or guessing your age, but it’s a learning style. Public schools get paid to produce people who can pass a test, so teach the test, and get a raise.

So internet searches become, type in a question, get an answer. Type in 300 blackout reloading data 190 grain accurate #9. You get a set of results that might bring you here.

If you know the history of the cartridge, you might try the same with 300 whisper and get a few more/different results.

What happens if you enter “Accurate arms reloading manual pdf”. Or “western powder reloading manual pdf” look for the information source instead of the pin point answer. All of a sudden you have 20+ years of loading manuals to look through and all the powders, with all the cartridges. You didn’t get the exact answer you were looking for, but you get a treasure chest full of information.

You might find something like this on page 2 or 3 of the results. But you have to take the time to read/research and find a lot of failures before a nugget. Find a manual, read the index. That’s research driven, vs answer driven

https://www.scribd.com/doc/36302640/Acc ... ding-Guide

Different year, different info.

Sheridan gauge, I would have to look at again. I might be off by .010”.
Overall length of the gauge is 1.270” (might be 2.260” so adjust accordingly)
If the bullet sticks out the bottom of the gauge, it’s safe to load to mag length, it won’t hit the lands
If you load to the bottom step, you have minimum cartridge base to shoulder datum line. Maximum headspace, more correctly, head clearance.
Loaded flush with the top level, maximum cartridge base to shoulder datum, minimum head clearance.
The step is .005”

When you look at the SAAMI drawing note the chamber headspace and cartridge base to datum specs will be maximum length with a -.010” minimum.

Note that if the case is 1.368” long, the bullet is sitting in the gauge on the step that would be the lands you can size the case so that the case head is flush with the top of the gauge multiple ways. Minimum base to shoulder, and the shoulder will not contact the point in the gauge as designed, it’s .010” off. Size to maximum and the bullet touches, shoulder touches, the base is still flush to the top.

You have to be aware of all three points. Your brass will last longer if you resize minimally. I use an actual measurement, but using the gauge I would resize to where the case head was within a couple thousandths from the top, or the middle step.

Always trim after sizing. With subs it’s harder to tell, but if you measure a. See before and after sizing, it will be longer after. Just opposite of before and after firing, it will be shorter.

Same amount of metal, if it gets fatter, the metal comes from the length, if you squeeze it from the sides, it pushes forward.

Same thing happens with the base to shoulder measurement. Before the shoulder contacts the die, the case squeezes in and moves the shoulder forward. When it hits the shoulder then it gets pushed into the neck as the shoulder move back. That’s when any stretching of the case shows up.

It can be real confusing the take a fired piece of brass, size it and actually have be shorter than when you first loaded it.

Long way to say I size brass .002” short for the chamber it will be used in.

Hope that helps some.
300 Blackout, not just for sub-sonics.
Augenblick
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Re: Where to go from here?

Post by Augenblick »

I'm coming up fast on 57, but only about 8 months reloading. I get what your saying.

Sometimes seeking answers nets you additional knowledge and information beyond the answer you were seeking. Like when you went to look up a word in a dictionary and came across others words that caught your intrest on your way to your goal. I would argue that seeking answers and finding information aren't mutually exclusive.

What I was noting was your experience and knowledge on the subject which you have gained over time. It takes some time to discover how much you don't know on a subject. There is the learning curve to figure out what are the right questions to ask. What do you need to answer to gain the information you seek?

When searching refinement is important. The fields are wide and full of chaff. It takes time to sift through it all. So I appreciate your experience and help to cut through to the answer I'm seeking and it is incumbent on me to process and understand the information.

I have searched a little more general as in 300 blackout reloading data accurate #9 but not specifically for a 190gr bullet. I do dig deeper than the first few pages of search results.

Thank you for the link to the accurate reloading guide. I really wanted to have a pressure ballpark.

I think I'm close on the Sheridan gauge. But I'll need a little adjustment on my sizing die.
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Re: Where to go from here?

Post by Augenblick »

These are Hornady 190gr sub-x blems. Fairly uniform and are 1.322". Defect appears to be in cannelure depth.
Image

Cannelure seems to be about .050" wide.
Image

So I took an empty case and seated to 2.26" OAL with Hornady 190gr sub-x. Neck diameter is .3328" - .333". I used a marker on ogive area dropped it in the chamber and sent the bolt home(no forward assist so I can't gently nudge it in). Extracted via charging handle and it was a bit sticky. After the rough chambering/extraction the OAL was 2.25".
Image

I put a bullet beside it and it looks like the bearing surface is in contact with about 3/4 of the neck before the boat tail begins.
Image

I gave it the same treatment a few more times and OAL was down to 2.242" and it extracted smoothly.

I did a second one and repeated the process.
Image
Red marks are seating rings. Not sure if I messed up seating cup with compressed CFE and hard cast bullets.

I looked at your suggestion a few posts back about the 180gr RN. Length1.168" flat base bullet OAL 2.05" 9.5 gr Accurate #9 1300fps. I considered it but it seems to me the Hornady 190gr SPBT with the same sectional density same length 1.329" OAL 2.185" 8.9 gr 12 fps seems a closer match.

So I'm really second guessing myself because you have so much knowledge and experience that I'm wondering what I am missing.

I'm going to seat another bullet to 2.22" and if I don't have any contact on the bullet I'll use that as my starting length.
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dellet
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Re: Where to go from here?

Post by dellet »

No internet tonight, posting by phone is a pain, so short and sweet.

Why do you care about sectional density?

Use the tools you have in an unconventional way.

Proper way to measure COL for jam is a special tool, Hornady headspace gauge can work.
Needed to andd that you anlso need the overall length gauge. Link below and you need the modified case. Basically norms like splitting a case neck, it’s just a loose neck.
https://www.midwayusa.com/product/1012747079

Splitting a case neck so the bullet slides in and out works, sear the bullet long insert by hand, pull it back out and the length is basically jam length.

Drop a bullet in your Sheridan, set a sized case on top, measure overall length, and cas base to the level your case matches on the gauge, subtract one from the other, that will be very close to maximum length.

Matching bullets for seated depth, it’s what inside that matter.

Case length + bullet length - COL = seared depth

1.365 + 1.335 - 2.25 = .450” in the case

Case + bullet length - seated depth = COL

1.365 + 1.255 - .450 = 2.14

In theory same seared depth, same pressure. Bullet weight will matter, but you can’t always get the same, I think the data I sent links for, you could have pressure readings, or correct bullet weight, but not both. Sometimes you have to wing it. One had subs, one had supers. At least you knew you wouldn’t be over pressure. Pick your greatest safety margin.

Now you know why I said I ignore cannelures. But since that bullet was designed for the blackout, Let’s see how close you get to that cannelure before it stops jamming.
300 Blackout, not just for sub-sonics.
Augenblick
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Re: Where to go from here?

Post by Augenblick »

Just finished at the range. Accurate #9 really performed. Full function at all charges. It was as quiet as I hoped.

Dellet I owe you a beer or even something stronger.
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dellet
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Re: Where to go from here?

Post by dellet »

Image

This thread might have some meaning now that you’ve been through it.
viewtopic.php?f=128&t=98869

I asked about sectional density, and it was a serious question. I probably know why it’s in the back of your mind, but there’s another consideration.

How was accuracy?
300 Blackout, not just for sub-sonics.
Augenblick
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Re: Where to go from here?

Post by Augenblick »

So today was mostly about not blowing my face off. Mission accomplished.

Full function, feeding, ejection, LRBHO mag dump all on normal/low gas setting. I didn't see any obvious pressure signs. I'll measure the cases later to be sure.

I did have one scare. With the cast bullets I removed the suppressor to make sure the bullets we're stabilizing and it was my first time firing the rattler with just the ASR muzzle brake. Out of the 5.5" barrel the report scared the crap out of me.

With the suppressor on It was so quiet. Completely hearing safe. It was finally what I wanted it to be. No unburnt powder.

For all my complaints with the limitations of the rattler it is really well gassed. Runs great, compact and well suited for a PDW.

Image
This was my best group 1.45". Best velocity lowest standard deviation. It was only 40 yards. Things went down hill from there with lower velocity. I would post the data but Caldwell app crashes when I try to view the data.

Image

Image

Image
Looks like the bottom round here and maybe the top keyholes.

Image
These were SVC 220gr not the sub-x. I wrote both.

So need to increase velocity a bit and work on accuracy.

So I brought up sectional density initially to compare bullets erroneously thinking it meant something it didn't. Then I learned that all bullets that are the same weight for a given caliber have the same sectional density.

I understand that the weight of the bullet has an effect on chamber pressure which was part of my thinking process.

Ultimately it is most important in terminal ballistics since the kinetic energy of a projectile is 1/2 mass *velocity squared so the energy of the bullet falls off exponentially with velocity. Something like that?

Have you had any experience with #41 primers and this powder with subsonic? I'm stating to look for information on that now since I have plenty of those on hand.
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dellet
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Re: Where to go from here?

Post by dellet »

It’s really not too bad for a start.

I generally use either #41 or 7 1/2 primers. A magnum primer will probably help you some. The 400’s are softer and might look a lot flatter than they would actually be based on pressure.

Sectional density does serve a function, but I was wondering how you were applying it. It’s often used to compare penetration, I thought you might be.

For penetration and stopping power, sectional density is pointless (almost). Bullet design is everything. It’s possible that a bullet with a higher S.D., will have less penetration, than a lower. Or a lighter bullet, can deliver more energy on target at lower speed. All depends on expansion.

What dumps more energy and has more stopping power?

A 250 grain bullet at 2000 FPS, that passes through 12” and is still going 1750 FPS, when it exits. Or a 190 grain bullet that hits at 1000 FPS, and stops at 6”?

My guess is that you’re well on your way to becoming a noise/muzzle blast snob :mrgreen:
300 Blackout, not just for sub-sonics.
Augenblick
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Re: Where to go from here?

Post by Augenblick »

These are the bases of the 8.5 gr Accurate #9 loads. The primers look like this.

Image

They look a bit flat but as you just mentioned the cci 400's are softer. They look exactly the same as the 10.5 grain H110 SVC 220gr primers and I know those were not over pressure.
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dellet
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Re: Where to go from here?

Post by dellet »

Top center is a good example. Looks like over pressure, and it probably is, for the primer.

Note the dimple from the firing pin is pushed back out and started to flow into the hole in the bolt face. Knowing the primer, it makes sense. If you posted a photo of just that primer and asked “is this load over pressure?” You would get a lot of, yes answers.

If you increase pressure too much, it could blow a hole. James Calhoun did a nice write up on primers, pressure and specs.

Lots of warnings about slam fires on soft primers, only a few have actually had it happen, but something to be aware of.

Looks like you’re off to a good start
300 Blackout, not just for sub-sonics.
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