Starline Brass Technical Discussion

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Starline Brass Technical Discussion

Postby Hoot » Sat May 20, 2017 6:48 pm

With more members getting this brass and to aid in visibility, I have renamed the thread. Please post observations once yours arrives.

Hoot


My friend Todd, who I shoot Rimfire BR with (Hoot's secret other passion), is a used and new brass rep. He knows of my passion for the 450b. He also knew that Starline was making 450b brass now. He stopped by today with a surprise. A bag of 50 of them, to have me evaluate. He bought a thousand of them as his customers have been inquiring about them. So, it being a rainy, cold (44 deg) day, I spent a good portion of it recording measurements of them, along with the few new Hornady brass I have saved.

They look like this:

Image

Finish is equal to hornady as far as I could tell:

Image

I have created a spreadsheet of the two brands:

starline brass.xlsx
(16.62 KiB) Downloaded 29 times


Here's the bottom line and my report to Todd. He will sell small lots if anyone wants some.

Image

Starline 450 Bushmaster Case Report

One of the 50 cases was short (indicated in red) to the point that it will in all likelihood, be out of tolerance after 1 firing. They shrink every time you fire them. Most after the first firing and then to lessening degrees each subsequent reload. that one case was not included in statistical analysis.

All tolerances were close enough to Hornady as to be negligible in difference. I would have liked the case head diameter to have been .003+ wider, but not being able to measure wall thickness all the way down, I dont know if it will be an issue after successive stout loads. Excessive pressure is measured in this caliber, not by the primer flattening, although that is always worthy of scrutiny. It is measured by case head growth. SAAMI spec is .5000 new. Unfortunately, Hornady deviated a little from the original 2008 SAAMI spec to keep people from using .284 Win brass (original parent case) so some of the dimensions are at the outer limit of that original SAAMI spec.

The extraction groove is narrower in the Starline brass. That is a good thing as it lessens any chance of any of the different brand bolt extractors bottoming out in the groove.

Hoot
Last edited by Hoot on Mon May 22, 2017 7:32 am, edited 2 times in total.
Reason: Renamed Thread
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Re: Starline Brass Technical Discussion

Postby paulmark3010 » Sun May 21, 2017 6:17 am

Loaded these Friday. Have not had a chance to shoot them yet. Great in the Sheridan gauge. :twisted:
Attachments
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Starline 1.jpg
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Re: Starline Brass Technical Discussion

Postby Al in Mi » Sun May 21, 2017 6:21 am

where you get the gauge? looks almost like it was made from a barrel drop
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Re: Starline Melody: Got Some Engineering Samples

Postby Hoot » Sun May 21, 2017 7:24 am

I wished I had a box of 50 new Hornady cases to compare 1:1 with the Starlines. I had a jar of 38 new cases. When I dug into it, a handful were pulled down R-P marked from back when I evaluated those Remington Accu-Tips (Green-tips) which I set aside as their tolerances were all over the place. A large number of the remaining new Hornady brass were already primed, so I couldn't measure their primer pockets. The unprimed new Hornady brass remaining were adequate to get averages however. Just not the statistically significant sample I would have preferred.

I emailed Todd the full Excel spreadsheet and when I got up, he had replied that he was satisfied with the evaluation.
He sells them on Gunbroker in as little as 50 case bags for folks who don't want to buy 250 in one crack. His price is about $1.00 less than Starline for 50 cases and $15.50 less than new Hornady brass listed on Midway When they have it in stock.

His GB handle is steyrpro2506 with an A+ (>2k reviews) rating.

Can't wait to get some of them out on the firing line myself.

IIRC Tony from Tromix once said that they make their case gauges from barrel drops. I've considered getting one for the amount of 450b reloading I do. Would have been good to have had access to one 2000 reloads ago. Now I just mic the caseheads and put them in jars marked <.5000, .5000-.5005, .5005-.5010, .5010-.5015 and >.5015. I won't reload any that are >.5015 even though my Bartz will successfully thunk up to something like .5018. My old loosey goosey Bushmaster upper would thunk .5020 caseheads.

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Re: Starline Brass Technical Discussion

Postby paulmark3010 » Sun May 21, 2017 2:29 pm

Al in Mi wrote:where you get the gauge? looks almost like it was made from a barrel drop

http://www.tromix.com. $45 :twisted:
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Re: Starline Brass Technical Discussion

Postby Hoot » Mon May 22, 2017 10:37 am

I haven't had a chance to do water volume test to get an idea of wall thickness yet, but I'd be negligent to not mention that I'm at least a little concerned over the case head size.

Background:
The case walls expand during ignition to the point where the chamber walls stop them. After the pressure goes down, they contract a little to allow the case to be extracted. This is one of the reasons for fire forming. The case diameter normally increases a little after first shot fire forming, often providing a little more powder capacity, which is a good thing. A part of the case, namely the web and below, being solid brass, do not expand more than barely measurable after each shot. That's a good thing too. Where it gets dicey is the spot where the case wall and the solid web portion meet. This is often where case head separation failure occurs. That is definitely not good. If the case wall is near the same diameter as the chamber wall, it doesn't expand much under pressure. If it is a lot less diameter than the chamber wall, it will obviously expand more on the first firing. When the case wall expands it creates stress upon the junction of it and the non (or little) expanding web. This is normally tolerated when the degree of difference is not great. If it is great, such as the wrong caliber (smaller) case in your chamber, the head often detaches from the case and all kinds of misfortune can be visited upon you and the rifle. Very definitely not a good thing!

As we use it:
The 450b chamber is SAAMI spec'd to be 0.501 ID in the region of the case head. That's all the greater it will allow the case to expand during ignition. I've seen 0.5015, even 0.5020, but never more. There is some wiggle room, but obviously you would not want that narrower than .501 if you want to be able to reliably chamber reloads and equally important, get them out once fired. Most of the new 450b brass I've seen either in factory loads or new reloading brass, run in the area of .499-.500 with the SAAMI spec being .5000 with no tolerance specified. So the chamber ID would limit the case growth from say .499 to .501 in a perfect world during ignition. It would then spring back a little once the pressure drops to allow for extraction. Brass is pretty ductile and that case wall to web junction tolerates that .002 expansion and contraction. When the case head area is .4955-.4960, such as encountered in the Starline brass, the expansion journey is more like .005, at least during first fire form. (That's why wildcat caliber fans don't use a max load to fire form their cases) If you have a loosey goosey chamber, it could be a little more.

This is where my knowledge runs low on fuel. I don't know if we need to be concerned about the longer "journey" that will be experienced using the Starline brass. Rest assured, I will be doing my homework, perusing the web for that information. For now. Don't load up lollapalooza first loads in your Starline brass. Start out with something more civil until we get some experiences under our belts, or until someone more knowledgeable wades in and corrects my misconception of this. Did I mention that this is a "gut feeling" concern? My recollection is not as good as it used to be, without more frequent refreshing.

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Re: Starline Brass Technical Discussion

Postby Hoot » Wed May 24, 2017 7:37 pm

It occurred to me that i left out some important metrics.
Case weight and water capacity as an indication of wall thickness.

For 20 cases of Starline, the average unprimed weight is 156.69gr with an SD of .526.
For 20 cases of Hornady, the average unprimed weight is 168.31gr with an SD of 2.73. An increase of 7% (more brass)
For Water Capacity, the Hornady holds 60gr and the Starline holds 61gr to overflow point.

Given the lighter weight and more water capacity in the Starline, chances are good that it has thinner case walls. What follows is conjecture: Given the narrower case head to wall junction area and what appears to be thinner walls, (end conjecture) I want to reiterate what I said earlier. Don't start off with "lolla palooza" loads right out of the chute with these cases.

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Re: Starline Brass Technical Discussion

Postby mcb » Thu May 25, 2017 7:30 am

Just cursious is that a calculated H2O capacity from cartridge weight and external dimensions or are you actually filling the cases with water after tarring the empty case on your scale?

The once fired Hornady brass I am using measured ~58.8gr of water when I weighted them full of water.
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Re: Starline Brass Technical Discussion

Postby Hoot » Thu May 25, 2017 7:55 am

mcb wrote:Just cursious is that a calculated H2O capacity from cartridge weight and external dimensions or are you actually filling the cases with water after tarring the empty case on your scale?

The once fired Hornady brass I am using measured ~58.8gr of water when I weighted them full of water.


These were unfired, factory sized brass, with a dead primer installed. The water in my shop is around 60 degrees. Water temperature factors in. I used to weigh mine with the meniscus at zero, since that's how we learned to do it in Chemistry class. Since QuickLoad references water capacity with the cases filled to overflow (max positive meniscus), that's how I now measure them. From experience, water capacity usually goes up after the first firing in most if not all calibers. Historically, my Hornady brass have always been at or darn near 60 after first fire resize with the inside really clean. Dirty insides make the capacity go down if for no other reason than it traps small air bubbles. Some times, filling them 3/4 full and vigorously tapping them will release the bubbles prior to topping them off.

I weighed the empty case on my digital scale, then with it still on the scale, carefully fill with a syringe, from the bottom up and note the new weight. Simple math after that.

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Re: Starline Brass Technical Discussion

Postby mcb » Thu May 25, 2017 8:26 am

Interesting. I assumed (incorrectly) that H2O capacity was to filled level with case mouth. I will have to try it at max positive meniscus and see what I get.
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