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Re: GS Custom Solids for 375 Cheytac
Hi Wade,
I have seen references to a "Lost River Bore" a number of times but cannot find any specific dimensions. GSC bullets are intended for standard SAAMI and CIP specification barrels. Therefore we build to conform to a bore diameter of .367" and a groove diameter of .376". What are the bore and groove dimensions of a Lost River Bore? Your barrel twist of 11.5" is not ideal for either the GSC 291gr or the 355gr SP bullets but, if there are a lot of 11.5" barrels out there, we will look at a dedicated 11.5 bullet.
Hi Wade,
I have seen references to a "Lost River Bore" a number of times but cannot find any specific dimensions. GSC bullets are intended for standard SAAMI and CIP specification barrels. Therefore we build to conform to a bore diameter of .367" and a groove diameter of .376". What are the bore and groove dimensions of a Lost River Bore? Your barrel twist of 11.5" is not ideal for either the GSC 291gr or the 355gr SP bullets but, if there are a lot of 11.5" barrels out there, we will look at a dedicated 11.5 bullet.
Re: GS Custom Solids for 375 Cheytac
The lost river bore is just .0002 over sized for the solid bullets with no driving bands. .367 bore
Almost all of the Cheytac rifles use a 11.5 twist barrel. Custom rifles vary from 12 twist to 10 twist and ofcourse some faster twists for the longer bullets.
Dave
The lost river bore is just .0002 over sized for the solid bullets with no driving bands. .367 bore
Almost all of the Cheytac rifles use a 11.5 twist barrel. Custom rifles vary from 12 twist to 10 twist and ofcourse some faster twists for the longer bullets.
Dave
Re: GS Custom Solids for 375 Cheytac
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Viersco</div><div class="ubbcode-body">The lost river bore is just .0002 over sized for the solid bullets with no driving bands. .367 bore
<span style="font-size: 17pt">Almost all of the Cheytac rifles use a 11.5 twist barrel.</span> Custom rifles vary from 12 twist to 10 twist and ofcourse some faster twists for the longer bullets.
Dave </div></div>
Gerard...help us ASAP.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Viersco</div><div class="ubbcode-body">The lost river bore is just .0002 over sized for the solid bullets with no driving bands. .367 bore
<span style="font-size: 17pt">Almost all of the Cheytac rifles use a 11.5 twist barrel.</span> Custom rifles vary from 12 twist to 10 twist and ofcourse some faster twists for the longer bullets.
Dave </div></div>
Gerard...help us ASAP.
Re: GS Custom Solids for 375 Cheytac
Thanks Dave. If a Lost River Bore is .367" diameter bore, would the groove diameter then be 0.375"? That would be the standard CIP spec for a 378 Weatherby Mag. From the CIP spec below we see that the USA 375 barrels are specified at a groove diameter of 0.375" and the Euro 375s are 0.376".
http://www.lothar-walther.de/brcms/pdf/2103.pdf
Calibre --- Bore mm - Groove mm - Bore In - Groove In - Twist
375 Wea Mag - 9.350 -- 9.530 ---- 0.368 ----- 0.375 ---- 12.0
378 Wea Mag - 9.320 -- 9.530 ---- 0.367 ----- 0.375 ---- 12.0
375H&H ------ 9.300 -- 9.550 ---- 0.366 ----- 0.376 ---- 12.0
375 WR ------ 9.300 -- 9.550 ---- 0.366 ----- 0.376 ---- 12.0
9.5x66 SEvH - 9.300 -- 9.550 ---- 0.366 ----- 0.376 ---- 12.0
376 Steyr --- 9.300 -- 9.550 ---- 0.366 ----- 0.376 ---- 12.0
Doing the bullet is not a problem as long as I know what the bore/groove/twist is and what the launch speed and intended target is.
Thanks Dave. If a Lost River Bore is .367" diameter bore, would the groove diameter then be 0.375"? That would be the standard CIP spec for a 378 Weatherby Mag. From the CIP spec below we see that the USA 375 barrels are specified at a groove diameter of 0.375" and the Euro 375s are 0.376".
http://www.lothar-walther.de/brcms/pdf/2103.pdf
Calibre --- Bore mm - Groove mm - Bore In - Groove In - Twist
375 Wea Mag - 9.350 -- 9.530 ---- 0.368 ----- 0.375 ---- 12.0
378 Wea Mag - 9.320 -- 9.530 ---- 0.367 ----- 0.375 ---- 12.0
375H&H ------ 9.300 -- 9.550 ---- 0.366 ----- 0.376 ---- 12.0
375 WR ------ 9.300 -- 9.550 ---- 0.366 ----- 0.376 ---- 12.0
9.5x66 SEvH - 9.300 -- 9.550 ---- 0.366 ----- 0.376 ---- 12.0
376 Steyr --- 9.300 -- 9.550 ---- 0.366 ----- 0.376 ---- 12.0
Doing the bullet is not a problem as long as I know what the bore/groove/twist is and what the launch speed and intended target is.
Re: GS Custom Solids for 375 Cheytac
Gerard,
When i asked Barney Lawton about the Lost River Bore he said it was a 367 that they lapped oversized. I talked with Ron at Benchmark barrels the other day and he said the ones they sent him to be rifled had 368 bores, 375 rifling.
Hope this helps?
Dave
Gerard,
When i asked Barney Lawton about the Lost River Bore he said it was a 367 that they lapped oversized. I talked with Ron at Benchmark barrels the other day and he said the ones they sent him to be rifled had 368 bores, 375 rifling.
Hope this helps?
Dave
Re: GS Custom Solids for 375 Cheytac
I agree with all the above. What I've heard confirms the same specs for LR bore. The issue I see for the manufacturer is that two different bullets will have to be very well controlled and labeled and identified on the website/order form.
I agree a 11.5 twist 325ish bullet is due. Many have asked for it, and it will save a bit of cost and recoil for the shooter, while adding speed and flatter trajectory (medium range). Not to mention most of them do not shoot 2000m+.
I can see why some small accuracy and speed differences have appeared between Euro rifles and US rifles. Would certainly see improvements with two seperate bullets.
I agree with all the above. What I've heard confirms the same specs for LR bore. The issue I see for the manufacturer is that two different bullets will have to be very well controlled and labeled and identified on the website/order form.
I agree a 11.5 twist 325ish bullet is due. Many have asked for it, and it will save a bit of cost and recoil for the shooter, while adding speed and flatter trajectory (medium range). Not to mention most of them do not shoot 2000m+.
I can see why some small accuracy and speed differences have appeared between Euro rifles and US rifles. Would certainly see improvements with two seperate bullets.
Re: GS Custom Solids for 375 Cheytac
Might be some issues with running a lighter bullet than 325gr in a 375CT Anthony... The case capacity is very under-utilized as it is with a 350gr bullet and retumbo... A 338CT with 300gr jacketed bullets already achieves this kind of high velocity performance and is probably gonna be a more appealing and better suited cartridge if your only interested in medium range shooting or with less recoil etc... kinda silly building a 375CT for short range shooting...?
I think the main problem is when some people find the LRBullet difficult to tune, they start to look elsewhere for other bullet options... Then they find their options limited esp when they have a LRBT bore and 11.5twist...
Might be some issues with running a lighter bullet than 325gr in a 375CT Anthony... The case capacity is very under-utilized as it is with a 350gr bullet and retumbo... A 338CT with 300gr jacketed bullets already achieves this kind of high velocity performance and is probably gonna be a more appealing and better suited cartridge if your only interested in medium range shooting or with less recoil etc... kinda silly building a 375CT for short range shooting...?
I think the main problem is when some people find the LRBullet difficult to tune, they start to look elsewhere for other bullet options... Then they find their options limited esp when they have a LRBT bore and 11.5twist...
Re: GS Custom Solids for 375 Cheytac
The 11.5 LRB twist is old technology and best thing is to re-barrel to a more modern twist like 1:10. A new barrel only costs about $500
1:10 twist will stabilize most NEW magazine compatible bullets. But if the marked "demands" a NEW light 375 bullet for old technology barrels I guess they will be made. From a ballistic point of view it makes no sense IMO. It would be kind of putting a smaller engine in a F1 racecar to get better gas millage
.
The shooters that bought a LRB 11.5 barrel set-up should begin realizing that it is NOT the way to go with a 375CT platform ELR system if one wants to precognitive
.
Cheers,
Master Diver
The 11.5 LRB twist is old technology and best thing is to re-barrel to a more modern twist like 1:10. A new barrel only costs about $500
1:10 twist will stabilize most NEW magazine compatible bullets. But if the marked "demands" a NEW light 375 bullet for old technology barrels I guess they will be made. From a ballistic point of view it makes no sense IMO. It would be kind of putting a smaller engine in a F1 racecar to get better gas millage
The shooters that bought a LRB 11.5 barrel set-up should begin realizing that it is NOT the way to go with a 375CT platform ELR system if one wants to precognitive
Cheers,
Master Diver
Re: GS Custom Solids for 375 Cheytac
333gr, will work in 1:11.5" LRB bore. Max muzzle velocity is 3500fps. Calculated BC is:
3500fps 0.875
2350fps 0.772
1200fps 0.551
Gyroscopic stability at muzzle is 1.2 and supersonic to about 1650m.
333gr, will work in 1:11.5" LRB bore. Max muzzle velocity is 3500fps. Calculated BC is:
3500fps 0.875
2350fps 0.772
1200fps 0.551
Gyroscopic stability at muzzle is 1.2 and supersonic to about 1650m.
Re: GS Custom Solids for 375 Cheytac
Gerald on your website alot of the new bullets you are offering aren't on there. Is there a new website?
Gerald on your website alot of the new bullets you are offering aren't on there. Is there a new website?
Re: GS Custom Solids for 375 Cheytac
TimResin,
We are going to update the SP bullets pages completely later this month. Getting the tech pages for individual bullets prepared is a mission. Often, non technical people build the pages and do not always understand what they are writing. We check, check and check again and mistakes still get through.
TimResin,
We are going to update the SP bullets pages completely later this month. Getting the tech pages for individual bullets prepared is a mission. Often, non technical people build the pages and do not always understand what they are writing. We check, check and check again and mistakes still get through.
Re: GS Custom Solids for 375 Cheytac
groper, I agree. Still, there is a need for it, as we can see, and let's not forget what CT started with in the 408 with the 305 grain bullet! There is/can be a need for light-fast bullets for short to medium ranges. It can be rather difficult to convince a customer his ideas and "needs" are unfounded and to buy, and carry, an additional rifle for that. Even convincing a person they need to rebarrel can be rough, when they would rather just go with a lighter bullet. That's the beauty of choice. Still, it's a good fit.
groper, I agree. Still, there is a need for it, as we can see, and let's not forget what CT started with in the 408 with the 305 grain bullet! There is/can be a need for light-fast bullets for short to medium ranges. It can be rather difficult to convince a customer his ideas and "needs" are unfounded and to buy, and carry, an additional rifle for that. Even convincing a person they need to rebarrel can be rough, when they would rather just go with a lighter bullet. That's the beauty of choice. Still, it's a good fit.
Re: GS Custom Solids for 375 Cheytac
Dave,
I am currently building a 375CT with a Stillers action. I plan to shoot Jamison solids and the 350GR Sierras. You are saying it is better to go with say a 1:10 twist for these longer projectiles and the standard .375 bore diameter? Please confirm bore diameter recommendation you are referring to. I am still shopping for a barrel maker for this rifle. Lawton is NOT an option.
Dave,
I am currently building a 375CT with a Stillers action. I plan to shoot Jamison solids and the 350GR Sierras. You are saying it is better to go with say a 1:10 twist for these longer projectiles and the standard .375 bore diameter? Please confirm bore diameter recommendation you are referring to. I am still shopping for a barrel maker for this rifle. Lawton is NOT an option.
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