2500 fps w/gas check .308 What Alloy will I need????

[Larry Gibson]

Google 22LR unbalanced bullets. You'll see the helical arc in the video. The RPM of those 22LRs is only 66k +/-. Increase the RPM to 140K to 190k and you can imagine the difference.

[gtgeorge]

I have seen those bullets and the wobbling bullets. But those are not accurate even at short distances which still has me scratching my head. I have been reading your many posts Larry and feel I have learned a lot and agree with most of them. This one I just don't see but understand you did detailed testing which I do need to go back over and look at when I get caught up a bit with work.

I am planning on working up some loads (my next project) for an AR10 308W which I was hoping for about 2300fps with a 175gr HP version of the MP 180 series. I use 3-3-94 and it is a 1:10 twist so I now wonder if I will get an accurate 250yard and under load. From what I read here it won't happen so I will watch for it and adjust my velocity accordingly.

[Grmps]

GT, you may want to go with lyman#2 5-5-90

92-3-3 for handgun up through regular cast bullet rifle loads. LG

90-5-5 has performed the best from 1750 fps up through 3000+ fps than any other ternary alloy. LG

[Oklahoma Rebel]

I am preparing to make a batch of 3.5/3.5/93 with.4-.5% cu for a 9.3X62 to go up to 2100 w/286gr and2300 w/250gr bboolits. it was ly#2 but it was to hard and it was breaking off at the crimp groove. do you think I will be able to accomplish those velocities, keeping in mind the .5% copper content?

[Larry Gibson]

Accomplishing those velocities safely should be easy enough with the right powders. Given a 14" twist any problems with accuracy will depend more on bullet design, consistency and quality of the cast bullet, fit and the lube used.

[oldblinddog]

This is what can be done with the right bullet and powder:
Attachment 200234

I didn't bring the chrony to the range this morning but I'm fairly certain this is up over 2400 fps. The barrel is a Krieger 1-12 twist stainless, 26" long. It is a Remington varmint contour. The bullet is the Accurate 31-160G or 30XCB FN.

[Oklahoma Rebel]

oldblinddog what alloy did you use for that group?

[OS OK]

This is what can be done with the right bullet and powder:
Attachment 200234

I didn't bring the chrony to the range this morning but I'm fairly certain this is up over 2400 fps. The barrel is a Krieger 1-12 twist stainless, 26" long. It is a Remington varmint contour. The bullet is the Accurate 31-160G or 30XCB FN.

Nice work...it's obvious that you did your part on the trigger!

[oldblinddog]

oldblinddog what alloy did you use for that group?

The alloy is ~92.9/3.xx/3.xx. I don't know the exact numbers. It has a little more tin than antimony if memory serves.

I went back and looked it up 92.9/3.68/3.41
5 lbs hardball with 3.8 lbs 16-1 (my pot is 10lbs)

[oldblinddog]

Nice work...it's obvious that you did your part on the trigger!

Thanks! I didn't mention before, but the trigger is a Timney 520CE set for me by Timney at 1lb. Trigger discipline is a must!
Here is the rifle:

[Larry Gibson]

Nice rifle, excellent HV shooting....

[oldblinddog]

Thank you

I have to say that, after reviewing your article on the NOE forum, I have most likely overestimated the velocity in my post above. 2200 is more realistic. The only way to know is to chronograph that load and I intend to do that later this week and report those results here.

[popper]

Why do you think groups open up so much more going from 100 to 200yds because of the RPM threshold?

Not jst the RPM threshold, but many more factors. Non-linear dispersion is caused by 'angle of attack' relative to trajectory, wind, gravity, spin of the earth, several more. Cast typically doesn't have the high BC of jacketed which don't get 'bent' as much in launch, etc.

why is the ten shot group so much more important than the three to five shot groups?

10 shots gives a better representation of 'cone of fire' than the 3 or 5 shots. 20 would be better but then the shooter really comes into play, i.e. tired? As in all QC, the larger the sample the better the data.

[bullseye67]

Good evening,
I have been casting and shooting pistol boolits for 35+ years. I have been casting and shooting rifle boolits at LOW velocity for almost as long. Several years ago I decided to up the anti with rifle boolits and tried without luck to get more speed while still holding the accuracy I was getting out to 100 yards with the slower loads.
Larry Gibson and his posts on this forum were instrumental in getting to shooting with consistent accuracy out to 200 yards and 2300 plus fps.
When at the range working up and then proving the different loads, I probably shot 500 plus rounds and then when I had what I wanted. Another 1000 making sure accuracy would hold from different shooting positions.
Everything Larry has said has happened....period. The results of his testing are posted for all to see. His scores and targets from competitions he enters are posted. His advice is always straight up and to the point.
Larry Keep posting and know that there are a lot of people that rely on the information you provide.
Thank you for all that you do!
Everyone have an awesome week

[Oklahoma Rebel]

copper, i love reading about your copper experiments and have been doing it right along with you, i am the one that used a stick welder to weld copper into liquid lead, with success, so i respect you alott, but the spin of the earth?!?! come on. was that sarcasm?? lol have a good day!-Travis

[OS OK]

SNIPER 101 Part 73 - Coriolis Effects on Rifle Bullets . . . https://www.youtube.com/watch?v=hiRa...BZi0vDCIcEPxUn . . . it even changes due to direction of trajectory and where you are on the earth in respect to the Equator...no kidding!

Nobody teaches it better than Rex...

[oldblinddog]

SNIPER 101 Part 73 - Coriolis Effects on Rifle Bullets . . . https://www.youtube.com/watch?v=hiRa...BZi0vDCIcEPxUn . . . it even changes due to direction of trajectory and where you are on the earth in respect to the Equator...no
kidding!

Nobody teaches it better than Rex...

Yes, and it affects airplanes and the weather as well.

[Oklahoma Rebel]

I have heard of the corialis effect, I watch a lot of history channel, was probably on one of those sniper shows like deadliest missions or something. still sounds crazy, lol-Travis

[popper]

And used for accurate inertial space navigation.

[Oklahoma Rebel]

blinddog I forgot to ask if that groups boolits were air cooled or heat treated. the reason I ask is by happenstance I am making a BIG batch of the same alloy but with .4-.5% copper to help when I get up to 2100-2300fps