So I was always looking to see if there was a direct link between Dan Newberry's OCW and Saterlee 10 shot method, and I have seen a few that put their two cents in. Being a data nut, I spent some time thinking of what controls could validate this information and came up with what I have here.
PREPARE FOR A LONG READ!
My second post will have the data, since I have to play with formatting for photos and such.
I am open to questions, but in regards to where I got the high speed tools/access to the range/what I do for work I will only say I have good friends that are just as passionate as I am about data and shooting.
Purpose
Which is the most efficient loading method between Optimal Charge Weight and a 10 round load test?
**10 round load test used at the reference name for Saterlee's development. I ended up using 30 rounds, 3 rounds per velocity reading
**OCW recommends a round robin type of shot, but I didn't want to deal with the pain of paying attention to which round I was shooting at which target so I did not do so
Equipment
Possible reasoning for deviations
I'm not doing this test again without some corporate/sponsorship help as it took up about 2 months to do over all. I'm hoping this is a guideline that gets refined for future tests.
PREPARE FOR A LONG READ!
My second post will have the data, since I have to play with formatting for photos and such.
I am open to questions, but in regards to where I got the high speed tools/access to the range/what I do for work I will only say I have good friends that are just as passionate as I am about data and shooting.
Purpose
Which is the most efficient loading method between Optimal Charge Weight and a 10 round load test?
**10 round load test used at the reference name for Saterlee's development. I ended up using 30 rounds, 3 rounds per velocity reading
**OCW recommends a round robin type of shot, but I didn't want to deal with the pain of paying attention to which round I was shooting at which target so I did not do so
Equipment
- Magnetospeed
- Factory rifle, 1100 rounds down range before this test
- Custom rifle with a 26 in, 1 in 7.5 twist bartlein barrel, 300 rounds down range before this test
- Rifle shot on sturdy platform/rest
- Indoor range at 100 yards
- Peterson Brass, volumetrically sorted +/- 0.05 gr of H20
- Berger Hybrids 140gr sorted by base to ogive, base to overall length, then tipped for consistency
- New h4350 power
- New lot of BR2
- Redding T7
- Redding full length resizing die, no bushing
- Redding competition seating die
- 2 different brand Analytical Balance, with magnetic force restoration reading 0.01 grains (Not an autotrickler sadly)
- 21st Century large primer pocket plug
- 1000 microliter micropipette
- Both hornady and SAP comparators used to see which yielded consistent results
- Values were different but accuracy/precision similar in both. SAP was easier to get consistent positions
- 2 mitutoyo 6 inch calipers
- Gordon's Reloading Tool
- The majority of the time was spent brass prepping and sorting.
- 750 pieces of 3x fired brass was sorted to get 54 pieces of brass with internal volumes
- Brass prep
- Neck turned to 13.5
- Hand deprimed with Frankford Arsenal
- Wet tumbled for 30 minutes
- Annealed
- Chamfer and deburred case neck
- Resized with full length sizing die without expander using imperial sizing die wax
- Case neck ID lubed with one-shot
- Expanded with 0.2615 gage pin for case neck tension of 0.0025
- Dry tumbled to remove extraneous lube for 4 hours
- Imperial dry neck lube for ID, extraneous lube on OD removed with cloth
- Hand primed with RCBS hand primer
- Powder weighed on two analytical balances using the same calibration weight, to confirm powder load +/- 0.02 grains from selected powder weight
- Powder left to sit for approximately 5 seconds on a fully closed scale
- Bullet seated via Redding T7 to the same length of 0.082in
- Transported via plastic containers that hold rounds at case body with no slack to move
- no less than 50.50 grains H20
- no greater than 50.70 grains of H20
- Brass prep
- Brass was of the same lot, using an AMP annealer with the setting of 149
- Brass was originally shot through a different rifle to expand brass without using a newer barrel
- Second firing was on custom rifle, at 158 shots already fired
- Third firing get a better fit in custom rifle. Added trimming of case neck after expanding, rechamfer/deburred, and began generalized volumetric sorting
- Case necks trimmed to be at 0.912in +/- 0.001
- Fourth firing, used for this test, volumetric to stated values
- 6 rounds of each charge weight were loaded during the same sitting, 3 for OCW and 3 for Velocity
- Volumetric data was gotten by use of deionized water at room temperatures between 62-68 degrees
- Water was not reused to avoid contamination
- Water poured in a glass be a erlenmeyer flask when ran out
- All done in one sitting to avoid major temperature variances (It sucked, do not recommend)
- Temperature gaged every 30 minutes in flask
- Water was measured to the top of case necks, with a small yet consistent meniscus
- Cases first had primer pocket plug inserted and placed on scale and left for 5-10 seconds to stabilize then tared to zero before adding water
- Live fire
- Live firing was done in one day
- Range was a 100 yard steel tube (This is not a public range at all.)
- Muzzle would be inside the tube via a small opening
- A metal steel bench was used, ensuring consistent placement
- Rifle was supported on steel bench with specially formed sandbags to prevent movement and remain on target
- Barrel of rifle sped up at round 195, so no deviation due to this variation occurred
- Barrel/chamber/muzzle break cleaned before test using a jag, to near spotless patches
- First 3 jag passes - Boretech Carbon Remover
- 4th pass - Dry
- 5th pass - CLP to wet bore
- Muzzle break, Area 419 Hellfire 3 port, was left in a bottle with Boretech carbon remover for 1 day, cleaned and repeated one more time to bring muzzle break back to new condition
- First 3 jag passes - Boretech Carbon Remover
- Rounds were first shot with OCW method, with one of OnTarget TDS's targets
- 5 rounds not associated with the test were loaded at the median of the selected charge weights to be used as sighters/clean bore shots
- 3 rounds would be shot consecutively, then a 5 minute rest would occur to let the barrel cool
- Shot groups measured via Gordon's Reloading tool
- Saterlee method shot afterwards
- Magnetospeed attached after barrel cooled
- 3 rounds loaded, then quickly fired with a similar 5 minute rest period
Possible reasoning for deviations
I'm not doing this test again without some corporate/sponsorship help as it took up about 2 months to do over all. I'm hoping this is a guideline that gets refined for future tests.
- During the Saterlee Test, I went ham and lost some data as noted in the satterlee chart.
- On the OCW part, on charge weight 39.8gr, I bumped the magazine off the table and it landed on the front of the mag. I did not want the data to be skewed, so I did not shoot the 38.9gr charge weight for OCW
- I did not move up charge weights by 0.1gr as Saterlee does, because I was getting frustrated sorting brass.
- I did not go beyond 41.2 grains because I did not want to load hot. I don't get pressure signs until 41.6 grains, but I didn't want to burn out another 6.5 barrel at 2300 rounds because I thought faster is better.
- I used Gordon's reloading tool to mark my shots by mouse, so target data could be off for OCW by minute amounts
- Rate of fire was not controlled
- I did not sort primers
- I did not, and do not chase lands until need be
- The barrel temperature should have been measured at certain points to ensure a constant firing temperature each time
- Though I did have an UPS battery on the closed analytical balances, there may have been electrical variations
- I did not have a measured line to measure the meniscus, so case neck length variation may lead to greater standard deviations in volume weight at the 0.01 place, hence I chose the 0.1 place to sort brass
- Primer pockets, once fired, are pushed upwards. This leads to a space between primer pocket plug and primer pocket where there is an extra drop of water. Considering how an extra drop of water could be 0.3 grains added, I used a micropipette to inject water to help with consistency but this could be a point of variation
- Once the brass was sorted, I loaded charge weights 39.6 to 40.4 with brass that was within 50.50gr to 50.60gr of water, but then realized I should have mixed it up. I did this at 40.6gr to 41.2gr. In my opinion, this may invalidate ranges in this part of the test
- I don't doubt my shooting abilities; between 2018-2019 I have a tracked amount 500,000 rounds tested, not added my personal range time or unaccounted firings. Pulling a trigger isn't the issue, but variances in breathing, parallax, cheek weld/etc could lead to variations in the last few groups on the OCW test as well
- I want to add in because this may be a factor, I took most of 2020 off most marksmanship due to burnout/pain. It sounds cool slinging this much lead down range, but the human body is NOT meant to handle with this many rounds down range.
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