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Old 02-19-2013, 12:01 PM   #1 (permalink)
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First Strike Round Dimensions and Weights

I noticed in another thread that someone was asking for FS Dimensions. I remembered that I put together some farily extensive measurements taken with a digital caliper / micrometer and, I figured that this sub-forum would be a good place to post it.

First off, these measurements were taken some time ago (approaching three years now) I cannot vouche for whether or not there have been changes (intentional or accidental) to the rounds since.

I'd also like to repeat these measurements and re-measure a sample set at least a couple times to determine the significance of my measurement error. I'll try to do this in the coming months.

So, with all that being said, below is what I have.

First up, length. Using the caliper, and measuring from the very tip of the fill nipple, to the tail, a round measured to .6805" and I didn't notice any significant differences between rounds (i.e. everything was around .680"). I'll document this more thoroughly in the future.


When it comes to diameter, this is where things got tricky. I had to resort to three measurements here. The Equator, and the Skirt in two axii.

The Equator (where the skirt is attached to the payload section) was straightforward. They measured out to be effectively circular at .6850" What made this challenging was consistently measuring on the seam as it is fairly narrow.


As for the skirt, I took two measurements- at the widest and the narrowest points, I will refer to them as the Y and X axii respectively. I did my best to measure from two opposing fin tips. And the pictures show this well in one image but, not so well in the other.
* The X-Axis (narrowest) came in at .6595"
* The Y-Axis (Widest) came in at .6755"



So, simply put, the skirt is somewhat lopsided and, the equator is the widest point of the rounds at .681"

I purchased an ammunition reloading scale. These are more accurate than the vast majority of scales you will find in other consumer stores. I measured two sets of 20 rounds, one from a box that was one month old, and the other from a box that was five months old. Before measuring I let the scale warm up and, I calibrated it with the included calibrtion weight (as per the manufacturers instructions).


I switched the units to grains (for finer resolution) and I found the following:
1mo old box:
  • Avg Weight: 47.94grains
  • 95% +/- .7875grains

5mo old box:
  • Avg Weight: 48.03grains
  • 95% +/- 1.4321grains

I will post the raw data to googledocs tonight for review. Data posted here.

At one point, I fired several rounds into my bathtub (full of water) to evaluate if the fins or shell were getting wear marks from the LAPCO/Tiberius rifled barrel. I found no noticable wear but, I recovered a complete shell, rinsed out the paint and found it to weigh 9.9grains.

Finally, in all the drawings and even the oversized 3D printed model that showed up on Facebook, the fins are depicted as having a squared cross section. In reality, the fins have a curved cross section, and you can see this if you look closely at the pics or, if you pick up your own rounds. I suspect it's within the limits of the manufacturing process (i.e. maybe they designed for squared but, they come out rounded).
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Quote:
Originally Posted by Tom Kaye -in response to FS price critics
Unfortunately all of you have played the one "speedball" game of paintball for so long you can't conceive of other ways to do this and hence any new ideas seem stupid.

Last edited by uv_halo; 03-04-2013 at 10:30 AM. Reason: I used a reloading scale, not reloading calipers.
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Old 02-19-2013, 08:04 PM   #2 (permalink)
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I did a similar project in the spring of 2012.



I weighed and measured each round the same way. I used a reloading caliper and a jewelry scale for measurements. One interesting note is the box of "blue" field paint averaged .6840 with 10 rounds measuring at .6830

Based on my average results, I came to a very similar conclusion, close enough to concur with UV Halo's findings.
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Old 02-19-2013, 10:19 PM   #3 (permalink)
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Thanks for sharing!
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Quote:
Originally Posted by Tom Kaye -in response to FS price critics
Unfortunately all of you have played the one "speedball" game of paintball for so long you can't conceive of other ways to do this and hence any new ideas seem stupid.
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Old 03-22-2013, 06:51 PM   #4 (permalink)
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Something just occurred to me... In a post somewhere I cant seem to find at the moment, someone was suggesting that weighing and measuring FSRs, and grouping them by size and weight could help increase consistency.

Now I have to wonder, when people test different barrels for accuracy, have the rounds been sorted?

Because if they have been sorted AND the consistency is better as a result, someone who does not sort their FSRs is not going to get results that are as good as the tests...
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Old 03-22-2013, 09:48 PM   #5 (permalink)
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The only non scientific measuring I did was with the SR1 shell sizers. This by no means is anything else but my experience and my own opinion.
I encourage people to do there own testing and learn how their gun shoots FS.

The sizers I use are .684 , .685 and .686

I would start with the 684 and size the 100 round box of FS .

Then I worked the FS thru the sizers until I had 3 different sized lots of FS .

The un-scientific part was how the FS felt going thru the sizer. I was going for a slight drag or tension to hold the FS in the sizer.

You cannot push a 686 thru a 684 sizer with out breaking them.

Every FS of course went thru the 686 and that is the sizer I use when I'm just casual shooting.

The thing I noticed the most while shooting un-sized FS in a small sizer was the vertical string varying quite a bit from over shooting the target to under shooting by 20 to 30 feet. That is why I made sizers.

The SR1 would not shoot a 686 FS thru a 684 sizer.
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Old 03-23-2013, 04:08 PM   #6 (permalink)
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Today, I decided to sort my FS rounds according to size, for use with my Dye DAM (main), and with my T9.1 (sidearm).

I had two new boxes of 100, and about 80 rounds from another 100 box.

For the DAM, I have two barrels, the stock one, which comes with a .688 back, and a Lapco 10in BigShot 0.690.

For the T9.1, I have a Lapco 9in Straightshot 0.686.

I started sizing the FSRs using the Dye UL back, and made two sets of rounds, ones (A) that could been blown through using only my breath, and ones (B) that could not.

All the B rounds slid through easily inside the BigShot.

Then I took the A rounds, and tried to see which ones would slide through the 0.686 barrel... all of them did, and seemed even looser than in the .688 back.

So I tried the sizing the B rounds with the Lapco Tiberius barrel, and they slide through the 0.686 barrel very easily.

My conclusion, based on these findings, is that one should sort their FS rounds using the barrel(s) one intends to use.

Side note: I also noticed a couple of rounds per box, and among my leftovers, that had fins that were slightly deformed or a bit crooked. I decided to keep these separately, for chronoing before games.
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