otis45
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Post by otis45 on Oct 27, 2015 16:16:01 GMT -8
What's the best twist rate for the 6x45? Have any of you had different twist rates on your BHW barrels for the 6x45, and if so what has been most accurate and worked best for you? And is there a difference in what the twist rate should be in a 18" vs 20" and if so what's the best for both
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Deleted
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Post by Deleted on Oct 27, 2015 17:20:39 GMT -8
What's the best twist rate for the 6x45? Have any of you had different twist rates on your BHW barrels for the 6x45, and if so what has been most accurate and worked best for you? And is there a difference in what the twist rate should be in a 18" vs 20" and if so what's the best for both I would go with a 1 in 9 twist. It will work with any bullet you can stuff in a 6x45 at mag length. In fact it will stabilize everything except the 105 and up, VLD style bullets. |
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Post by GLSHOOTER on Oct 27, 2015 18:27:43 GMT -8
Same 1:9 from 16" to 24". I shoot the 1:9 to 500 with an 87 grain and it does well. No need for the 1:8.
Greg
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Post by gaberelli on Oct 28, 2015 3:49:29 GMT -8
I assume the same thing applies for the 6x6.8 since its traveling even faster. My 1:9 shot the 90 grain well and I never shot 100 or heavier.
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Post by GLSHOOTER on Oct 28, 2015 9:15:57 GMT -8
I assume the same thing applies for the 6x6.8 since its traveling even faster. My 1:9 shot the 90 grain well and I never shot 100 or heavier. Yes it will work for that very well according to the hundreds of rounds I've put through mine at distance. If a guy can push a heavier bullet faster he can often make up for almost one step of slower twist rate. We see this in the little 223-6 MM frequently. In the bigger 30 cals and up it gets a bit less frequent but not unheard of if you have some extra horsepower available on tap. Greg |
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otis45
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Posts: 44
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Post by otis45 on Oct 28, 2015 11:45:53 GMT -8
Thanks for the help! I'm glad I asked cuz was planning on going 1:8. Can ya'll tell me why the 1:9 is better then the 1:8 for this round? What's the disadvantages or advantages to both? Just for my curiosity and interest of knowledge for myself, thanks
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Post by GLSHOOTER on Oct 28, 2015 12:31:29 GMT -8
Thanks for the help! I'm glad I asked cuz was planning on going 1:8. Can ya'll tell me why the 1:9 is better then the 1:8 for this round? What's the disadvantages or advantages to both? Just for my curiosity and interest of knowledge for myself, thanks It stabilizes the best weight bullets used in the 6X45 adequately. It will tend to shoot the lighter, as in 58's, extremely well. The 1:8 comes into play when you get up in the 105-107 range and for the 6X45 this steals too much case capacity to get adequate velocities out of the big pills. No huge disadvantage if you go 1:8 but I feel it is just better balanced with a 1:9 spin rate. Nothing major just a subtle finesse thing in performance. Greg |
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otis45
Junior Member
Posts: 44
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Post by otis45 on Oct 28, 2015 16:07:38 GMT -8
Cool, good to know! Kinda what I figured, just little different thought then with the 5.56 when trying to get the larger rounds. And with the 5.56 you need the 1:8 or 1:7 to staplize the heavyer rounds, rounds at the same weight as the lighter 6mm...maybe a dump question but why is the better twist different between the 5.56 and 6mm with round same weight projectile.? Thanks again for all the help.
Ok little of topic but couple little small questions...
The 6x45 is more accurate then the 5.56 because of the better BC of the larger/heavy projectile correct? Also hits harder as well for same reason? But must be moving slower as well for same reason right?
And one more question...is there much difference in price with 5.56 and 6mm bullets/projectiles and on average what is that difference?
Sorry bout all the questions on going on bout this
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Post by geepee3 on Oct 28, 2015 17:41:43 GMT -8
Ok little of topic but couple little small questions... The 6x45 is more accurate then the 5.56 because of the better BC of the larger/heavy projectile correct? Also hits harder as well for same reason? But must be moving slower as well for same reason right? And one more question...is there much difference in price with 5.56 and 6mm bullets/projectiles and on average what is that difference? Sorry bout all the questions on going on bout this With the same weight bullet. The bullet shot from the 6x45mm will shoot slightly faster with less of a pressure curve than its 5.56/.223 counterpart. There are a few dynamics involved. 6mm projectiles have less length than 5.56/.223 projectiles of the same weight. The bearing surface is less also, meaning less friction as it travels up the barrel. Base of the 6mm bullets having a larger surface area helps impart more energy.  Here are four 75 gr. bullets. The one far left is a Hornady .223 Match 75 gr. HPBT. Next are the 6mm 75 gr. bullets in order L-R; Speer, Sierra and Hornady. With the bullets seating less in the case allows for more powder and less pressure. The bore diameter also accounts for pressure reduction.  This shows the contrast in seating depth. All these bullets are seated at the same COAL of 2.250". Far left is the Hornady .223 Match 75 gr. HPBT. Next is a Sierra 6mm 70 gr.HPBT. Speer 6mm 75 GR. HP. Berger 6mm 80 gr. HP. Last is a Sierra 6mm 85 gr. HPBT. The Hornady 6mm 87 gr. HPBT I have are .020" shorter than the Hornady .223 Match 75 gr. HPBT bullets. These are some of the reason I chose the 6x45mm. Mostly because I knew I wanted to shoot between 70-90 grain bullets. The 6x45mm does so with greater efficiency than the 5.56/.223. As to price, your going to pay a little more for bullets with the 6x45mm. I have two BHW barreled 6x45mm rifles, both 1:9 twists. one 18" mid-length, one 20" rifle length. For some reason I shoot the 18" the most. Basically because it was the first AR I ever assembled. Glenn |
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Post by bobatl on Oct 28, 2015 17:44:18 GMT -8
Very well done Glenn, kudos..
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Post by GLSHOOTER on Oct 29, 2015 6:27:04 GMT -8
Geepee you did a great job on that explanation. Thanks.
One thing that was not mentioned is that the 6X45 is not in itself more accurate than a 223. This will be load and barrel specific. Increasing the bore size doesn't necessarily help anything other than speed with the same weight bullets and a potential access to better BC bullets that may or may not be of value.
The 24 case moved up to 25 has consistently shown a bit of degradation no matter what case is the parent in my experience. I have no earthly idea why but the 25's just aren't fast. Accuracy also never seems quite as good. Not that it can't be good it just seems like off the shelf they take a bunch more tinkering.
Greg
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otis45
Junior Member
Posts: 44
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Post by otis45 on Oct 29, 2015 11:27:11 GMT -8
Geepee wow thanks that is awesome! The pictures really help bring it all together and explanation was great. Makes things very clear now.thanks a lot!
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otis45
Junior Member
Posts: 44
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Post by otis45 on Oct 29, 2015 11:28:19 GMT -8
Geepee you did a great job on that explanation. Thanks. One thing that was not mentioned is that the 6X45 is not in itself more accurate than a 223. This will be load and barrel specific. Increasing the bore size doesn't necessarily help anything other than speed with the same weight bullets and a potential access to better BC bullets that may or may not be of value. The 24 case moved up to 25 has consistently shown a bit of degradation no matter what case is the parent in my experience. I have no earthly idea why but the 25's just aren't fast. Accuracy also never seems quite as good. Not that it can't be good it just seems like off the shelf they take a bunch more tinkering. Greg |
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otis45
Junior Member
Posts: 44
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Post by otis45 on Oct 29, 2015 11:30:09 GMT -8
Geepee you did a great job on that explanation. Thanks. One thing that was not mentioned is that the 6X45 is not in itself more accurate than a 223. This will be load and barrel specific. Increasing the bore size doesn't necessarily help anything other than speed with the same weight bullets and a potential access to better BC bullets that may or may not be of value. The 24 case moved up to 25 has consistently shown a bit of degradation no matter what case is the parent in my experience. I have no earthly idea why but the 25's just aren't fast. Accuracy also never seems quite as good. Not that it can't be good it just seems like off the shelf they take a bunch more tinkering. Greg Thanks for that, good to know. It's all coming together thanks for all the help everyone! |
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Post by geepee3 on Oct 29, 2015 13:46:51 GMT -8
Thanks Guys! Geepee you did a great job on that explanation. Thanks. One thing that was not mentioned is that the 6X45 is not in itself more accurate than a 223. This will be load and barrel specific. Increasing the bore size doesn't necessarily help anything other than speed with the same weight bullets and a potential access to better BC bullets that may or may not be of value. The 24 case moved up to 25 has consistently shown a bit of degradation no matter what case is the parent in my experience. I have no earthly idea why but the 25's just aren't fast. Accuracy also never seems quite as good. Not that it can't be good it just seems like off the shelf they take a bunch more tinkering. Greg Well said Greg, on the accuracy side of the issue. It really depends on the barrel. With the two 6x45mm rifles I have. It's interesting how some bullets will shoot good in both. Some will shoot good in the 18" barrel but not the 20" barrel. And vise versa. Your mentioning of the 24 cal. verses the 25 cal. has got me thinking. I'm starting to get ready to do another 6.8 SPC wildcat. Have 25x6.8 on my mind. But after seeing BiggerHammer's post on the Mule Deer with the 6x6.8 I'm rethinking things. Decisions, Decisions. Glenn |
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