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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
284win help
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<blockquote data-quote="tim_w" data-source="post: 2698727" data-attributes="member: 11132"><p>My recommendations:</p><p></p><p><strong>* Barrel:</strong> 1:8.5 Twist (Large buffer to std 300k RPM limit. Largest option for bullet choices trad and mono.)</p><p></p><p><strong>*</strong> <strong>Chamber Reamer:</strong> Freebore + 1°3' (Freebore length to allow longest body bullet to seat above shoulder junc (doughnut zone) with a bit of extra to length allow for seating depth wiggle room. My guess is 0.190"+</p><p></p><p><strong>* Action: </strong>Long Action (3.5"+ = no worries about running into a Max COAL limit)</p><p></p><p><strong>* Bullet Recommendation: </strong>(Based on 150-160 limit) 150BDII & 155HH (+ traditional hunting bullets)</p><p></p><p><strong>* Blah Blah Blah:</strong></p><p>That is a SAAMI Spec Reamer. It's got zero FB and a extreme shallow leade angle of 0°44'33' vs the more traditional precision throats with an actual FB and leade of 1°30'. I have no experience with such a shallow leade angle outside long throated compound angled leades that start ½° then transion to 1°3'-5'+ to full bore. One thing I would question is the rate of leade erosion with such little land material/length.</p><p></p><p>I personally would not want the std SAAMI throat of zero FB and super shallow leade which is less that ½ a degree angle. For 150-160 bullets to include high BC monos you will likely be in a 0.180"-0.190" FB with a more tradional 1° 30' leade.</p><p></p><p>If I had to pick just 2 bullets for typical hunting which tends to be much lower vol vs varmint/target where component cost is not as much a priority it would be 150 BDII by Badlands and 155 HH by Hammer. For support look at the long Hammer & Badlands Bullet performance threads. </p><p></p><p>While you can tend to get away with less twist below 1.5SG for a given bullet usually down to 1.2 plus any or altitude offset it will tend to yaw the bullet more/sooner on impact. Monos IME are less forgiving to going below the 1.5SG depending on design. At 284 W velocities having a bit more twist is only a benefit. I would run a 1:8-8.5 twist. I can not think of a single negative on performance. Even with a MV of 3200fps bullet with 8.5tw RPM is still under 275k well under the generally accepted 300k limit for jacketed bullets. </p><p></p><p>The 8.5 twist will allow you to run ANY cup-n-core bullet right up to the 195s plus in the 150-180 monos all but the most radical long nosed monos in that weight range. Example would be the 160gr Super Bulldozer II which is listed to need a 1:7 vs the std 150 Bulldozer II which 1:8.5. For Hammers more tangent noses the 8.5tw is good thru 170gr. (They do have a new design line of higher BC bullets that will be released.that is exciting) I hate to be restricted on bullets or where, what temp, vel combo I can use. To me it's always best to keep options open when it comes to general LR hunting setups. Especially when there is no practical downside in this case. Bullet blowup are not an issue for the cartridge bullet barrel specs.</p></blockquote><p></p>
[QUOTE="tim_w, post: 2698727, member: 11132"] My recommendations: [B]* Barrel:[/B] 1:8.5 Twist (Large buffer to std 300k RPM limit. Largest option for bullet choices trad and mono.) [B]*[/B] [B]Chamber Reamer:[/B] Freebore + 1°3' (Freebore length to allow longest body bullet to seat above shoulder junc (doughnut zone) with a bit of extra to length allow for seating depth wiggle room. My guess is 0.190"+ [B]* Action: [/B]Long Action (3.5"+ = no worries about running into a Max COAL limit) [B]* Bullet Recommendation: [/B](Based on 150-160 limit) 150BDII & 155HH (+ traditional hunting bullets) [B]* Blah Blah Blah:[/B] That is a SAAMI Spec Reamer. It's got zero FB and a extreme shallow leade angle of 0°44'33' vs the more traditional precision throats with an actual FB and leade of 1°30'. I have no experience with such a shallow leade angle outside long throated compound angled leades that start ½° then transion to 1°3'-5'+ to full bore. One thing I would question is the rate of leade erosion with such little land material/length. I personally would not want the std SAAMI throat of zero FB and super shallow leade which is less that ½ a degree angle. For 150-160 bullets to include high BC monos you will likely be in a 0.180"-0.190" FB with a more tradional 1° 30' leade. If I had to pick just 2 bullets for typical hunting which tends to be much lower vol vs varmint/target where component cost is not as much a priority it would be 150 BDII by Badlands and 155 HH by Hammer. For support look at the long Hammer & Badlands Bullet performance threads. While you can tend to get away with less twist below 1.5SG for a given bullet usually down to 1.2 plus any or altitude offset it will tend to yaw the bullet more/sooner on impact. Monos IME are less forgiving to going below the 1.5SG depending on design. At 284 W velocities having a bit more twist is only a benefit. I would run a 1:8-8.5 twist. I can not think of a single negative on performance. Even with a MV of 3200fps bullet with 8.5tw RPM is still under 275k well under the generally accepted 300k limit for jacketed bullets. The 8.5 twist will allow you to run ANY cup-n-core bullet right up to the 195s plus in the 150-180 monos all but the most radical long nosed monos in that weight range. Example would be the 160gr Super Bulldozer II which is listed to need a 1:7 vs the std 150 Bulldozer II which 1:8.5. For Hammers more tangent noses the 8.5tw is good thru 170gr. (They do have a new design line of higher BC bullets that will be released.that is exciting) I hate to be restricted on bullets or where, what temp, vel combo I can use. To me it's always best to keep options open when it comes to general LR hunting setups. Especially when there is no practical downside in this case. Bullet blowup are not an issue for the cartridge bullet barrel specs. [/QUOTE]
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