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Reloading
Making your own 7LRM brass
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<blockquote data-quote="P7M13" data-source="post: 1939562" data-attributes="member: 94154"><p>A fellow member here, outside the US, contacted me asking how I made 7LRM brass. He stated that Gunwerks wouldn't ship him their ADG made 7 Long Range Magnum brass. While I don't know the truth of that, I said I was happy to supply info on how to convert brass to make your own. Here we go... Comments, suggestions and criticism invited!</p><p></p><p><strong>Procedure for necking down 375 Ruger to 7mm LRM</strong></p><p><em>Pictures for reference</em></p><p>[ATTACH=full]202990[/ATTACH]</p><p></p><p><strong>Dimensional Information:</strong></p><p></p><table style='width: 100%'><tr><td><div style="text-align: center">Cartridge</div> </td><td><div style="text-align: center">OAL</div> </td><td><div style="text-align: center">Neck<br /> Length</div> </td><td><div style="text-align: center">Shoulder<br /> Length</div> </td><td><div style="text-align: center">Shoulder<br /> Diameter</div> </td><td><div style="text-align: center">Shoulder<br /> Angle</div> </td><td><div style="text-align: center">Shoulder<br /> Δ Length</div> </td><td><div style="text-align: center">CW Die<br /> Turns for<br /> Setback</div> </td></tr><tr><td>7LRM</td><td><div style="text-align: right">2.514</div> </td><td><div style="text-align: right">0.382</div> </td><td><div style="text-align: right">1.965</div> </td><td><div style="text-align: right">0.511</div> </td><td><div style="text-align: center">30°</div> </td><td><div style="text-align: center">0.000</div> </td><td><div style="text-align: center"></div> </td></tr><tr><td>300 PRC</td><td><div style="text-align: right">2.580</div> </td><td><div style="text-align: right">0.308</div> </td><td><div style="text-align: right">2.127</div> </td><td><div style="text-align: right">0.515</div> </td><td><div style="text-align: center">30°</div> </td><td><div style="text-align: center">0.162</div> </td><td><div style="text-align: center">6 + 209°</div> </td></tr><tr><td>375 Rug</td><td><div style="text-align: right">2.580</div> </td><td><div style="text-align: right">0.305</div> </td><td><div style="text-align: right">2.179</div> </td><td><div style="text-align: right">0.515</div> </td><td><div style="text-align: center">30°</div> </td><td><div style="text-align: center">0.214</div> </td><td><div style="text-align: center">7 + 96°</div> </td></tr></table><p></p><p><strong>Parts Needed for reforming 375 Ruger</strong></p><ul> <li data-xf-list-type="ul">338 RCM FL die</li> <li data-xf-list-type="ul">300RCM FL die</li> <li data-xf-list-type="ul">7mm SAUM FL die</li> <li data-xf-list-type="ul">Neck Turning tool (currently use Forster)</li> </ul><p><strong> Parts Needed for reforming 300 PRC</strong></p><ul> <li data-xf-list-type="ul">300PRC FL die</li> <li data-xf-list-type="ul">7mm SAUM FL die</li> <li data-xf-list-type="ul">Neck Turning tool (currently use Forster)</li> </ul><p><strong>Steps to Convert 375 Ruger (haven't done from 300 PRC)</strong></p><p></p><p>Remove mandrel/decap pin from 338 RCM</p><p>Install 338 RCM die into single stage press (RCBS Rock Chucker or equivalent), back die out as much as possible.</p><p>Think of the press lever as a protractor with vertical being 0° and the full stroke being ~140°. On my Lee Classic Cast, home position is -7°, full stroke is 133°. Since I desire to move the shoulder down 214 mils (0.214"), I want to set my die in the press so my ram movement from the point of the shoulder engaging the die to the setback desired is 214 mils. On my press, that starts at 107° of lever angle.</p><p>Why? Setting the shoulder back must be done at an extremely slow ram speed or you will collapse the case. Also, the best way to achieve accurate size conversion is when your travel is limited by hard stops.</p><p>Set a case in your ram, move the lever to the proper angle of travel, and use something to hold it there. Then screw the die down until it just contacts the mouth of the case.</p><p>Return the ram to home position, then screw the die in further, the number of turns in the table on page 1.</p><p>Then lube your case. This is an instance where light lube does not help you. Don't be messy either. I will wipe on a 0W-20 Mobil 1 for this.</p><p>Run the ram up to the point of engagement, then VERY SLOWLY finish the stroke. By very slowly, this should take approximately 15 seconds from first contact, and move even slower for the last 10 seconds.</p><p>There is a reason you move extremely slowly. If you don't, this is what your cases will look like (fugly doesn't do it justice):</p><p></p><p>[ATTACH=full]202991[/ATTACH]</p><p></p><p>If they do turn out like this, you're moving too fast, and throw the case out.</p><p>Check your shoulder length against the 1.965" in the table above. Adjust your die accordingly. Too long, and it'll never fit in your chamber. A little short, and you'll just fireform the case. Your first firing is considered a fire-form anyway…</p><p>Housekeeping suggestion: be sure you set your locking ring on your die for when you form new cases. Hornady split ring cases are the best for this.</p><p>After you have taken the 375 Ruger case, necked it down to 338 and set the shoulder back, trim the case to 2.525" OAL.</p><p>Now neck turn the case to 13 mils thickness.</p><p>Anneal the cases.</p><ol> <li data-xf-list-type="ol">Remove the decap and expander mandrel from your 300 RCM, then install the die on the press. Put one of your annealed cases, well lubed, into the ram and run it up to approximately 90°. Screw in the die so it is touching the case mouth.</li> <li data-xf-list-type="ol">VERY SLOWLY (e.g. 10 seconds) run the ram up until you feel the resisting pressure where the shoulder is contacting the die. This can be difficult to feel near full ram travel. Never force anything if your ram doesn't want to move with consistent pressure.</li> <li data-xf-list-type="ol">If need be, do this step near the top of the ram stroke so you have a better sense of when the case shoulder engages the die.</li> <li data-xf-list-type="ol">Remove and examine your case. You want to see FULL neck resizing, all the way down to the junction of the shoulder. Any bulges here, and your case will probably not chamber properly.</li> <li data-xf-list-type="ol">If you did your job, recheck your dimensions. As above, any folds and you're moving too fast (discard the case).</li> <li data-xf-list-type="ol">If all is good, neck turn the case back to 13 mils neck web thickness.</li> <li data-xf-list-type="ol">Back the die out. Put the case into the ram, run it all the way to full stroke and then turn the die down slowly until it's fully engaging the case. Set your locking ring on the die.</li> <li data-xf-list-type="ol">Set this case aside as a setup template.</li> <li data-xf-list-type="ol">Resize the necks on the remaining cases.</li> <li data-xf-list-type="ol">Trim to 2.515 OAL,</li> <li data-xf-list-type="ol">Neck trim to 13 mils.</li> <li data-xf-list-type="ol">Reize the necks again with the expander mandrel in place.</li> <li data-xf-list-type="ol">Anneal the batch.</li> </ol><p>Repeat steps 1-13 with your 7 SAUM FL die.</p><p>Fireform.</p><p>Here are finished loaded cases.</p><p>One is GW Hornady brass, one is my conversion.</p><p>[ATTACH=full]202992[/ATTACH]</p><p></p><p><strong>Reloading</strong></p><p>I have a set of the 7LRM Hornady Custom Dies from Gunwerks. I think they are crap. Seriously.</p><p>I took a set of 375 Ruger dies and shortened the die to do a FL when necessary. For the most part, I will just do a neck size with the 7 SAUM die.</p></blockquote><p></p>
[QUOTE="P7M13, post: 1939562, member: 94154"] A fellow member here, outside the US, contacted me asking how I made 7LRM brass. He stated that Gunwerks wouldn't ship him their ADG made 7 Long Range Magnum brass. While I don't know the truth of that, I said I was happy to supply info on how to convert brass to make your own. Here we go... Comments, suggestions and criticism invited! [B]Procedure for necking down 375 Ruger to 7mm LRM[/B] [I]Pictures for reference[/I] [ATTACH type="full" alt="1594489749607.png"]202990[/ATTACH] [B]Dimensional Information:[/B] [TABLE] [TR] [TD][CENTER]Cartridge[/CENTER][/TD] [TD][CENTER]OAL[/CENTER][/TD] [TD][CENTER]Neck Length[/CENTER][/TD] [TD][CENTER]Shoulder Length[/CENTER][/TD] [TD][CENTER]Shoulder Diameter[/CENTER][/TD] [TD][CENTER]Shoulder Angle[/CENTER][/TD] [TD][CENTER]Shoulder Δ Length[/CENTER][/TD] [TD][CENTER]CW Die Turns for Setback[/CENTER][/TD] [/TR] [TR] [TD]7LRM[/TD] [TD][RIGHT]2.514[/RIGHT][/TD] [TD][RIGHT]0.382[/RIGHT][/TD] [TD][RIGHT]1.965[/RIGHT][/TD] [TD][RIGHT]0.511[/RIGHT][/TD] [TD][CENTER]30°[/CENTER][/TD] [TD][CENTER]0.000[/CENTER][/TD] [TD][CENTER][/CENTER][/TD] [/TR] [TR] [TD]300 PRC[/TD] [TD][RIGHT]2.580[/RIGHT][/TD] [TD][RIGHT]0.308[/RIGHT][/TD] [TD][RIGHT]2.127[/RIGHT][/TD] [TD][RIGHT]0.515[/RIGHT][/TD] [TD][CENTER]30°[/CENTER][/TD] [TD][CENTER]0.162[/CENTER][/TD] [TD][CENTER]6 + 209°[/CENTER][/TD] [/TR] [TR] [TD]375 Rug[/TD] [TD][RIGHT]2.580[/RIGHT][/TD] [TD][RIGHT]0.305[/RIGHT][/TD] [TD][RIGHT]2.179[/RIGHT][/TD] [TD][RIGHT]0.515[/RIGHT][/TD] [TD][CENTER]30°[/CENTER][/TD] [TD][CENTER]0.214[/CENTER][/TD] [TD][CENTER]7 + 96°[/CENTER][/TD] [/TR] [/TABLE] [B]Parts Needed for reforming 375 Ruger[/B] [LIST] [*]338 RCM FL die [*]300RCM FL die [*]7mm SAUM FL die [*]Neck Turning tool (currently use Forster) [/LIST] [B] Parts Needed for reforming 300 PRC[/B] [LIST] [*]300PRC FL die [*]7mm SAUM FL die [*]Neck Turning tool (currently use Forster) [/LIST] [B]Steps to Convert 375 Ruger (haven’t done from 300 PRC)[/B] Remove mandrel/decap pin from 338 RCM Install 338 RCM die into single stage press (RCBS Rock Chucker or equivalent), back die out as much as possible. Think of the press lever as a protractor with vertical being 0° and the full stroke being ~140°. On my Lee Classic Cast, home position is -7°, full stroke is 133°. Since I desire to move the shoulder down 214 mils (0.214”), I want to set my die in the press so my ram movement from the point of the shoulder engaging the die to the setback desired is 214 mils. On my press, that starts at 107° of lever angle. Why? Setting the shoulder back must be done at an extremely slow ram speed or you will collapse the case. Also, the best way to achieve accurate size conversion is when your travel is limited by hard stops. Set a case in your ram, move the lever to the proper angle of travel, and use something to hold it there. Then screw the die down until it just contacts the mouth of the case. Return the ram to home position, then screw the die in further, the number of turns in the table on page 1. Then lube your case. This is an instance where light lube does not help you. Don’t be messy either. I will wipe on a 0W-20 Mobil 1 for this. Run the ram up to the point of engagement, then VERY SLOWLY finish the stroke. By very slowly, this should take approximately 15 seconds from first contact, and move even slower for the last 10 seconds. There is a reason you move extremely slowly. If you don’t, this is what your cases will look like (fugly doesn't do it justice): [ATTACH type="full" alt="1594489854015.png"]202991[/ATTACH] If they do turn out like this, you’re moving too fast, and throw the case out. Check your shoulder length against the 1.965” in the table above. Adjust your die accordingly. Too long, and it’ll never fit in your chamber. A little short, and you’ll just fireform the case. Your first firing is considered a fire-form anyway… Housekeeping suggestion: be sure you set your locking ring on your die for when you form new cases. Hornady split ring cases are the best for this. After you have taken the 375 Ruger case, necked it down to 338 and set the shoulder back, trim the case to 2.525” OAL. Now neck turn the case to 13 mils thickness. Anneal the cases. [LIST=1] [*]Remove the decap and expander mandrel from your 300 RCM, then install the die on the press. Put one of your annealed cases, well lubed, into the ram and run it up to approximately 90°. Screw in the die so it is touching the case mouth. [*]VERY SLOWLY (e.g. 10 seconds) run the ram up until you feel the resisting pressure where the shoulder is contacting the die. This can be difficult to feel near full ram travel. Never force anything if your ram doesn’t want to move with consistent pressure. [*]If need be, do this step near the top of the ram stroke so you have a better sense of when the case shoulder engages the die. [*]Remove and examine your case. You want to see FULL neck resizing, all the way down to the junction of the shoulder. Any bulges here, and your case will probably not chamber properly. [*]If you did your job, recheck your dimensions. As above, any folds and you’re moving too fast (discard the case). [*]If all is good, neck turn the case back to 13 mils neck web thickness. [*]Back the die out. Put the case into the ram, run it all the way to full stroke and then turn the die down slowly until it’s fully engaging the case. Set your locking ring on the die. [*]Set this case aside as a setup template. [*]Resize the necks on the remaining cases. [*]Trim to 2.515 OAL, [*]Neck trim to 13 mils. [*]Reize the necks again with the expander mandrel in place. [*]Anneal the batch. [/LIST] Repeat steps 1-13 with your 7 SAUM FL die. Fireform. Here are finished loaded cases. One is GW Hornady brass, one is my conversion. [ATTACH type="full" alt="1594489990492.png"]202992[/ATTACH] [B]Reloading[/B] I have a set of the 7LRM Hornady Custom Dies from Gunwerks. I think they are crap. Seriously. I took a set of 375 Ruger dies and shortened the die to do a FL when necessary. For the most part, I will just do a neck size with the 7 SAUM die. [/QUOTE]
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