BBT's at NOE

[sixshootertexan]

I'm very interested in the 135 and 154gr in .308. I just can not commit to buying anything right now. I will get a mold of each as soon as I can afford it.

[rsterne]

I understand about not committing right now.... but please indicate your interest, and then when/if there is a group buy you can jump in if you want.... This is to give Al some indication where to start....

Bob

[sixshootertexan]

OK I'll go ahead a register and post on each mold.

[rintafile]

I'm very interested in the 135 and 154gr in .308. I just can not commit to buying anything right now. I will get a mold of each as soon as I can afford it.

It may take several months to get that 10 buyers. Main thing is there is coming interested buyers now and then...There is so many molds at on lists that when it goes on mill that even takes week or so. tooling ordering take several days. There is plenty of time to wait I promise You.And that just says You are interested that not mandatory thing...Some people draw back even when group buy is on going but like Al ones says better jump of then that GB than not paying that mold when it is ready. And if I remember correctly there is 60 days timeline to pay that mold when it is ready

Edit: OK I see You find that topic.

[KnifeMaker]

I have posted my interest there!

Thanks Bob!

Knife

[shamu25]

Bob
I am comparing the .408  252 gr boattail on the Accurate Mold site to the 266 gr boattail on this post.  I have a 40 cal Extreme from Brent.  Which of the two should be more accurate and effective on deer.
Thanks Ray

[rsterne]

The NOE bullet is slightly longer, with a narrower boattail, a longer ogive, and a bit heavier, so it should have a better Ballistics Coefficient.... It will, however, require a somewhat faster twist because of those changes.... I am recommending a 23" or faster twist for the new NOE bullet.... the Accurate had a recommended twist of 26" or faster.... I do not know what twist rate Brent uses in the Extreme .408.... They both have the same diameter Meplat, and the weight is close, so there should be no difference in their performance on game.... In the proper twist barrel, there should be no particular difference in accuracy.... although the better BC will mean less wind drift with the NOE bullet.... They both have the same length supported by the rifling, greater than one caliber....

Bob

[shamu25]

Thank you Bob for your reply. This is very helpful and much appreciated. I think the twist rate is one in 22

[Allen A]

Thank you Bob for your reply. This is very helpful and much appreciated. I think the twist rate is one in 22

Hello Ray...You may want to check with Brent...pretty sure its 1-32 twist...kind regards, Al.

[FredSG]

My Extreme .408 has a 1:32 twist

FredSG

[shamu25]

I think you guys are correct. I must have been thinking of another gun

[Gr8Gorilla]

I'm interested. Where can we get faster twist barrels to stabilize the longer boolits?

I know that my ballistics program recommended that I use a 1:13" twist barrel for stabilizing the H&N Piledriver.

What is the lightest. 217" BBT that could be produced with one of these molds? I would like to try some in my springers if I can get them at a light enough weight.

Also interested in .30 or 7.62mm slugs in the 50+ range.q

[rsterne]

It is not practical to create a boattail in a really short bullet.... there is not enough length left for the bearing area.... The absolute minimum length I can do is 1.25 calibers, although 1.5 calibers is better....In .30 cal, there is a 1.25 cal long design, it weighs 68 gr.... If that bullet was scaled down to .250 cal it would be 39 gr.and require a 22" twist.... and in .217 cal it would be 26 gr. and need a 19" twist... At 1.5 calibers long in .30 cal the weight is 80 gr.... In .25 cal that would be 46 gr. and require an 18" twist.... and in .217 cal it would be 30 gr. and need a 16" twist.... If anyone wants cast bullets of those weights, please post in the Airgun Board at NOE, giving your reasons, and I will submit them to Al and hopefully he will include them in his catalogue....

Bob

[sixshootertexan]

Bob do you use G1 or G7 on the ballistics calculators for this bullets?

[rsterne]

The program that Al at NOE uses calculated the BC using the G1 Model.... I usually use that as well because it is much more commonplace.... Since we are not interested in Supersonic, and both are relatively flat in terms of the Cd in the Subsonic range, there isn't a huge difference in the shape of the curves, only the baseline, in other words the value of the BC.... Nobody else uses G7 for the types of bullets used in airguns, they are all using G1, so I don't see any point in comparing apples to oranges....

The only proper way is to use a Doppler Radar to determine the Cd over the entire velocity range as the bullet slows down, and I hope someday to have a LabRadar to collect that data.... Then I will be able to develop my own Drag Model for the BBTs....

Bob