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Rifles, Reloading, Optics, Equipment
Reloading
.375 H&H 300g bullets best velocity
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<blockquote data-quote="benchracer" data-source="post: 886782" data-attributes="member: 22069"><p>I was able to get some more testing done recently. I performed a seating depth test and a powder charge run up with the now discontinued Hornady 300g BTSP and H4350. </p><p> </p><p> I also did a basic min/max run up with the 350g SMK and H4350, H4831, and RL17.</p><p> </p><p> I am not to the point in testing where I have arrived at any definitive results, so I don't have any pics to share. I am hoping that my next round of tests will yield more useable results.</p><p> </p><p> Prior to testing, I mounted a Zeiss Conquest 4.5-14x44 AO scope on my rifle. It made life much easier while testing loads from the bench.</p><p> </p><p> For my seating depth test, I loaded three rounds each to COAL's of 3.830; 3.790; 3.750; and 3.710 using 78g of H4350, Norma brass, and CCI Magnum primers. I then fired the assembled loads in round robin fashion @ 100 yards. </p><p> </p><p> The first two rounds from the group seated to 3.830 cut overlapping holes. I don't know where the third round went.</p><p> </p><p> The first two rounds from the group seated to 3.790 were likewise touching, with the third round expanding the group to about 1.5".</p><p> </p><p> The group seated to 3.750 formed a nearly equilateral triangle approximately 1.75" across.</p><p> </p><p> The group seated to 3.710 formed another nearly equilateral triangle about 2.5" across.</p><p> </p><p> Both the 3.830 and 3.790 seating depths look like they really want to shoot. I intend to re-test both COAL's at my next opportunity (probably in the spring).</p><p> </p><p> For the powder charge run up, I loaded three rounds each @ 78.6, 79.4, 80.2, 81.0, and 81.8g of H4350 respectively, seated to a COAL of 3.830, and fired my OCW test @ 100 yards in round robin fashion. To my surprise, every group from 79.4 on up printed a neat triangle about 2" across. The 78.6g powder charge printed two rounds touching with a third round about 1.5" from the first two.</p><p> </p><p> In an attempt to reduce the number of rounds I would have to fire in a single bench session, I had cut off the bottom two powder charges, expecting best accuracy to be found from the middle to the high end of the spectrum. That now appears to me to have been a mistake. The fact that the 78.6g charge printed two rounds touching and produced the smallest group in the powder charge run up, taken together with the results of the seating depth test, is strongly suggestive to me that best accuracy with this powder and bullet may indeed be found at the lower powder charges. Once I establish the preferred seating depth, I intend to do a powder charge run up from 77.0g (Hodgdon book min) to 78.6g in an attempt to find best accuracy from this combination.</p><p> </p><p> If I am unable to find a sub-MOA combination, I intend to try RL-17 and RL-15. My efforts may be complicated by the fact that Hornady has recently discontinued the 300g BTSP (I hope this means there is a new .375 bullet on the way. An SST would be nice). I may have to substitute the Sierra 300g BTSP to continue my testing much beyond H4350.</p></blockquote><p></p>
[QUOTE="benchracer, post: 886782, member: 22069"] I was able to get some more testing done recently. I performed a seating depth test and a powder charge run up with the now discontinued Hornady 300g BTSP and H4350. I also did a basic min/max run up with the 350g SMK and H4350, H4831, and RL17. I am not to the point in testing where I have arrived at any definitive results, so I don't have any pics to share. I am hoping that my next round of tests will yield more useable results. Prior to testing, I mounted a Zeiss Conquest 4.5-14x44 AO scope on my rifle. It made life much easier while testing loads from the bench. For my seating depth test, I loaded three rounds each to COAL's of 3.830; 3.790; 3.750; and 3.710 using 78g of H4350, Norma brass, and CCI Magnum primers. I then fired the assembled loads in round robin fashion @ 100 yards. The first two rounds from the group seated to 3.830 cut overlapping holes. I don't know where the third round went. The first two rounds from the group seated to 3.790 were likewise touching, with the third round expanding the group to about 1.5". The group seated to 3.750 formed a nearly equilateral triangle approximately 1.75" across. The group seated to 3.710 formed another nearly equilateral triangle about 2.5" across. Both the 3.830 and 3.790 seating depths look like they really want to shoot. I intend to re-test both COAL's at my next opportunity (probably in the spring). For the powder charge run up, I loaded three rounds each @ 78.6, 79.4, 80.2, 81.0, and 81.8g of H4350 respectively, seated to a COAL of 3.830, and fired my OCW test @ 100 yards in round robin fashion. To my surprise, every group from 79.4 on up printed a neat triangle about 2" across. The 78.6g powder charge printed two rounds touching with a third round about 1.5" from the first two. In an attempt to reduce the number of rounds I would have to fire in a single bench session, I had cut off the bottom two powder charges, expecting best accuracy to be found from the middle to the high end of the spectrum. That now appears to me to have been a mistake. The fact that the 78.6g charge printed two rounds touching and produced the smallest group in the powder charge run up, taken together with the results of the seating depth test, is strongly suggestive to me that best accuracy with this powder and bullet may indeed be found at the lower powder charges. Once I establish the preferred seating depth, I intend to do a powder charge run up from 77.0g (Hodgdon book min) to 78.6g in an attempt to find best accuracy from this combination. If I am unable to find a sub-MOA combination, I intend to try RL-17 and RL-15. My efforts may be complicated by the fact that Hornady has recently discontinued the 300g BTSP (I hope this means there is a new .375 bullet on the way. An SST would be nice). I may have to substitute the Sierra 300g BTSP to continue my testing much beyond H4350. [/QUOTE]
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.375 H&H 300g bullets best velocity
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