RPM/Powder burn rate driven bullet weight decision: 22 Creed- 26" 7 Twist- H4350- Alpha

[spife7980]

So I have a 22 creed and Im in a feedback loop on what I should shoot. I had initially wanted an 85 rdf but Im thinking about hornadys now too since there is just more data out there for hornady in the creed that I can find in the depot and elsewhere for comparison.

I have a 26" 7 twist barrel
I have alpha small primer brass.
I have a new jug of H4350 for powder, dont really want to hunt down slower powders.

So numbers Im seeing for top end speeds, (correct me if your info disagrees). I see 75s reported to be 34-3500 fps, Im seeing 80s at 3300 fps, Im seeing 88s at 3100 fps.

With my 7 twist ALL of these are really friggin spinning.
A 75 at 3400=350k rpm
An 80 at 3300=340k rpm
An 88 at 3100=320k rpm


I know I see lots of reports about the 88 spinning apart at these speeds, some claim its because the same jacket is used in all thee of these bullets so to hold the extra material in the heavier bullets the jacket get stretched thinner.

If so, could it be in a margin where a 75 at 350k rpms might be able to hold together better than the 88 at 320k? And if that is the case do we think that the 80 might be on one side or the other? I dont see much about the 80 really though, dont know why.







My other thought, is that since I have h4350, which is faster than the rl26 that many seem to like, that a lighter 75-80 gr bullet might be a better match with that burn rate period?

 

[b6graham]

95smk worked best from my 22LRV (6xc parent case)

37.6gr H4350. 95smk at 3150 easily could probably hit 3300 without a sweat

88s were going poof on me. same charge at 3175

25" 7 twist 4 groove kreiger

 

[spife7980]

The 95 can handle 325k rpm but the 88 cant handle 320k. (33 cents vs 19 cents sure is a hard pill to swallow though)

The H4350 really lets you go that fast with the heavies? I havent seen anyone really pushing them that hard with h4350 only the lighter bullets. The 22LRV should only be a fraction of a hair smaller case volume, not a substantial amount right?

 

[b6graham]

The 95 can handle 325k rpm but the 88 cant handle 320k. (33 cents vs 19 cents sure is a hard pill to swallow though)

The H4350 really lets you go that fast with the heavies? I havent seen anyone really pushing them that hard with h4350 only the lighter bullets. The 22LRV should only be a fraction of a hair smaller case volume, not a substantial amount right?

i havent even done a max speed test. got a good SD at 3150 with the 95s and that was all i needed

 

[Ranger188]

With the 88's I ran into pressure before I got close to a full case (80%) with H4350
That's when I started testing RL26, N165, IMR4955, had the best speeds and least pressure with RL23
I ran the 75's and had blowups with those too. (later on)
Had a 26 inch 7 tw Hawkhill
Never had a problem till the 400 round count, then after that, tried the different bullets
to see if that would fix the problem, they all started to go.
Don't know if it was one thing or another, but tried a couple things to fix it. No go
Pulled the barrel and gave up on it.
I would go with the 80.5 or the new 85.5 Bergers or the Sierra 95's
Haven't heard much going wrong with them yet.

 

[spife7980]

With the 88's I ran into pressure before I got close to a full case (80%) with H4350
That's when I started testing RL26, N165, IMR4955, had the best speeds and least pressure with RL23
I ran the 75's and had blowups with those too. (later on)
Had a 26 inch 7 tw Hawkhill
Never had a problem till the 400 round count, then after that, tried the different bullets
to see if that would fix the problem, they all started to go.
Don't know if it was one thing or another, but tried a couple things to fix it. No go
Pulled the barrel and gave up on it.
I would go with the 80.5 or the new 85.5 Bergers or the Sierra 95's
Haven't heard much going wrong with them yet.

So the 75s blew too once the bore started to get a bit scratchy at 400 rounds... did you work up to test where they started to spin apart at?

 

[Ranger188]

Sorry, I just went to find my notes and only have the 88's H and 90g smk's
I'm pretty sure I tried them towards the end. My smith suggested them
cause he thought they might hold together better. I didn't get threw much testing
with them before they started going. The box of 100 is still pretty full. I was in the 3400 fps range
with those.
I was pushing my loads pretty good at first and maybe between that and a barrel problem
it cause they to go. Have had many HH barrels and always been great.
Cleaned it A LOT and just had very early fire cracking. At the 200 round count.
Between the fire cracking and the higher RPM's is what did the bullets in.
At the end, really slowed them down and still had the problem, but by then the barrel was
too far gone I think for anything to help it.
If I did it again, would definitely go with a 7.5 tw and run the 85.5 or 95g and keep the speeds
under 3150, but then what's the point.
It was a learning experience.

 

[Ranger188]

When I contacted Berger about the problem, was using their 90g.
They said to keep the RPM's below 300,000
This was a video of a 90g blowing up, wouldn't load, so stopped the frame.
The white dot is it going poof.

 

[spife7980]

Well darn, so far everything is pointing to going heavier.

 

[mcfred]

I blew up some 95SMKs on new Krieger 4-groove 1:7 pushing them only 3100fps, faster was worse. It was a tighter than usual bore though which I suspect is a contributing factor, I don't recall any issues with 85RDFs but I'd have to look at my notes. I didn't try the 88ELDs. I swapped to a 6-groove 1:8 and haven't had any issues with the 88ELDs at 3150fps (my elevation is 5000'+ so they're stable in an 8").

 

[Ranger188]

You could always go with one of the all copper bullets.
No blowups.
I think that's why your starting to see a few more 22br's
less powder, less heat, less problems.
Good luck.

 

[spife7980]

Id rather sell this barrel than pay warner prices. Ill probably just wait it out until the 85 rdf blems pop up now.