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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Len's new 7 LRM - first day at the range
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<blockquote data-quote="AZShooter" data-source="post: 821646" data-attributes="member: 5219"><p>Len,</p><p></p><p>After reading your thead this past winter I partially blame you for causing me to make a 7mm/375 Ruger. I had a box of 375 Ruger brass I purchased a few years ago. I wanted to neck it down to 7mm but never got around to it. I followed this thread and it was the catalyst. </p><p></p><p>I decided to go about this differently than Gunwerks . I have a ton of dies and decided to see if I could neck down the 375 case with things on hand. I didn't try to move the shoulder for a longer neck. </p><p></p><p>Fortunately I have a Whidden 338 RCM bushing/FL sizer die along with 338 RCM Hornady dies. The RCM and 375 share the same shoulder angle as well as diameter. I began my quest to make the 7mm/375. After using six steps with a variety of dies I got to 7mm. </p><p></p><p>Ordered a .317" neck 7mm/375 Ruger reamer from PT&G. I have an old lathe and do my own barrel chambering.</p><p></p><p>I took a Redding 7mm Rem mag competition seater die and recut the body guide with my 7mm/375 reamer. It works great!</p><p></p><p>Turned the necks to .013" and used the Whidden 338 RCM bushing die with the appropriate bushing for sizing the neck. The only die I purchased was a RCBS 375 Ruger FL and seater set. I use the FL die for partial FL sizing. </p><p> </p><p></p><p>First experiment was to rechamber a 7mm Rem mag. Barrel is a short 22" but it gave me a chance to try some things. Obviously it wouldn't give me the velocities but I could learn what powders would suit the case. Tried H1000 and then moved to RL-33 with a moly coated 180 hunting VLD. It shot well with the 180 going 2980 with 84 gr of RL-33.</p><p></p><p>A friend sold me a SS 30" #5 fluted Lilja 1 in 9 that was a 7mm STW with almost 400 rounds through it. After setback and rechambering it is 29 1/2". I began load development with the (no moly) Berger 180 target hybrid and 82 gr of RL-33 working up to 85 grs. 85 was slightly over the top. Settled on 83 grs for velocity of 3175 fps. Tested rifle out to 500M and it shot very well. Come ups matched JBM predictions using Berger's G7 BC of .345. </p><p></p><p>I realize the 7mm LRM has slightly less powder capacity but thought I'd share the results with RL-33 and 180 gr bullets. I would suggest if anyone wants to try this powder with the 7mm LRM to start around 80 gr and work up. </p><p></p><p>Your last comments on another coming back to report prompted me to share the above. Hope it is helpful to other 7mm/375 owners as well as similar variants like the 7mm-300 win mag or the 7mm Mashburn.</p></blockquote><p></p>
[QUOTE="AZShooter, post: 821646, member: 5219"] Len, After reading your thead this past winter I partially blame you for causing me to make a 7mm/375 Ruger. I had a box of 375 Ruger brass I purchased a few years ago. I wanted to neck it down to 7mm but never got around to it. I followed this thread and it was the catalyst. I decided to go about this differently than Gunwerks . I have a ton of dies and decided to see if I could neck down the 375 case with things on hand. I didn't try to move the shoulder for a longer neck. Fortunately I have a Whidden 338 RCM bushing/FL sizer die along with 338 RCM Hornady dies. The RCM and 375 share the same shoulder angle as well as diameter. I began my quest to make the 7mm/375. After using six steps with a variety of dies I got to 7mm. Ordered a .317" neck 7mm/375 Ruger reamer from PT&G. I have an old lathe and do my own barrel chambering. I took a Redding 7mm Rem mag competition seater die and recut the body guide with my 7mm/375 reamer. It works great! Turned the necks to .013" and used the Whidden 338 RCM bushing die with the appropriate bushing for sizing the neck. The only die I purchased was a RCBS 375 Ruger FL and seater set. I use the FL die for partial FL sizing. First experiment was to rechamber a 7mm Rem mag. Barrel is a short 22" but it gave me a chance to try some things. Obviously it wouldn't give me the velocities but I could learn what powders would suit the case. Tried H1000 and then moved to RL-33 with a moly coated 180 hunting VLD. It shot well with the 180 going 2980 with 84 gr of RL-33. A friend sold me a SS 30" #5 fluted Lilja 1 in 9 that was a 7mm STW with almost 400 rounds through it. After setback and rechambering it is 29 1/2". I began load development with the (no moly) Berger 180 target hybrid and 82 gr of RL-33 working up to 85 grs. 85 was slightly over the top. Settled on 83 grs for velocity of 3175 fps. Tested rifle out to 500M and it shot very well. Come ups matched JBM predictions using Berger's G7 BC of .345. I realize the 7mm LRM has slightly less powder capacity but thought I'd share the results with RL-33 and 180 gr bullets. I would suggest if anyone wants to try this powder with the 7mm LRM to start around 80 gr and work up. Your last comments on another coming back to report prompted me to share the above. Hope it is helpful to other 7mm/375 owners as well as similar variants like the 7mm-300 win mag or the 7mm Mashburn. [/QUOTE]
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Len's new 7 LRM - first day at the range
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