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I made loads for comparison using Clays & Titegroup powder. I'm looking for an accurate load with a light power factor for shooting in the Production Division in USPSA competition with my full size MP40. Power factor is bullet weight x velocity/1000. Minor power factor is 125 for Production. That said I'm looking for an accurate load in the 135 to 145 range - something that shoots with minimal recoil but accurate.



The bullet used was Precision 185gr RNFP loaded to an OAL of 1.125. Brass was once fired mixed head stamps and the primer used was Winchester small pistol. Chrono used was a CED temperature was about 72 degrees with a low humidity. The MP 40 was shot off of sandbags - targets were set at 30 feet. POA was flat line across the bottom of the image to make sure the tops of the sights are perfectly aligned. The "valley" provides an index for the front sight.



When setting up the powder charges I made 3 throws at that amount then weighed 5 throws to be sure that the averages were close to what I wanted. The Standard Deviation (SD) in the chrono test told the tale there. I had very tight SD readings through out my testing.

The loads were as follows:

Clays 3.1, 3.2, 3.3, 3.4, 3.5



Titegroup 3.7, 3.8, 3.9, 4.0



Since starting to shoot in March I have been using the Clays 3.1 load. What a suprise I got!



The results are as follows



Clays 3.1 Soft load but not very accurate. Group is about 3.5” above POA. Average velocity was 724 FPS with a SD of 5. This load made a PF of 133.9





Clays 3.2 Another soft load but not very accurate at all! Shots were well left & 3” above POA. Velocity was 728FPS with a SD of 5. This load made a 134.6 PF



Clays 3.3

Clays 3.3 Another soft load but not very accurate at all! Shots were well left & 3” above POA. They didn’t group very well Velocity was 723FPS with a SD of 6. This load made a 133.75 PF





Clays 3.4 Much more consistent but still not a good showing. Velocity was 739FPS with a SD of 4. This load made 136.7 PF.





Clays 3.5 The best of the Clay’s loads. Group appears to be decent. Velocity was 768FPS with a SD of 3. This load made 142 PF.





Titegroup 3.7 Not too bad – shooting a bit left of POA but much tighter than any of the Clays loads. Velocity was 782FPS with a SD of 7. This load made 144.6 PF.





Titegroup 3.8 Not too bad either. Just a bit left of POA but still a good looking group. Velocity was 792FPS with a SD of 4. This load makes 146.5 PF.





Titegroup 3.9 Getting better! First 2 shots right near POA the other 3 are respectable placements This load had a bit of snap to it – not as soft as all the previous tests Velocity was 812 FPS with a SD of 3. This load makes 150 PF.





Titegroup 4.0 Oh man this is it this is THE load! This load has much more snap than any of the others! Muzzle lift was really noticeable to me – even off of sandbags. Velocity was 826FPS with a SD of 8. This load makes 152.8 PF.



I learned a lot about reloading during that test fire/chrono session. One lesson learned is that a tenth of a grain can make an accuracy difference. Another lesson learned is that there is a distinct difference in load results between tiny amount of powder changes as well as powder manufacturers. It’s been stated here that “A chrono is a must to anybody serious about working up loads” – I agree very strongly to that statement.



My biggest dilemma now is which load to shoot in Production. Do I use a load that is deadly accurate at a 152PF (snappy load) or use a marginally accurate softer load like the Clay’s at 3.5 making 142 PF? It shoots much softer than the most accurate load but then again I need all the accuracy help I can get!



Any thoughts out there?
 

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Throwin Lead said:
My biggest dilemma now is which load to shoot in Production. Do I use a load that is deadly accurate at a 152PF (snappy load) or use a marginally accurate softer load like the Clay’s at 3.5 making 142 PF? It shoots much softer than the most accurate load but then again I need all the accuracy help I can get!



Any thoughts out there?


My 40 minor load chronos at about a 150pf :wink:
 
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