any reason to switch off of H4350 in the shorter barrel?

Good question. Tagging in to wait for an answer from someone who knows more than I.

No reason if it shoots well with that particular rifle. Going to a slightly faster powder may give you less muzzle flash and recoil impulse but at a cost of less velocity.
Powder that gets the most speed from a long barrel also gets the most speed in a short barrel…not that H4350 gets max velocities from the 6.5 Creedmoor anyway. That award goes to 4000MR and Reloder 26 and Staball

Hold on a minute. Let me give you some information, since you are also so helpful.

.308 bolt action 20-24" barrel H-Varget is the powder, we all know that.

.308 AR, 16" 155 gr TMK 2600 fps MV using IMR-8208

.308 bolt action 16" barrel, 155 gr TMK 2540 fps MV

How is the gas gun making more speed than the bolt action? Powder burn rate.

Buzz, stay with H-4350 and it'll make a great load. Then work up a load with H-Varget and let us know your findings. Be a giver instead of a taker all the time.

Different barrels, different guns. Some barrels are just faster than others. Loaded for 2 Remington 7mmSTW that were straight factory guns and one made 200fps more fps than the other with the same load.

Head space is a big player as well.

HS is HS...that's not the player you're thinking, it's freebore.

To illustrate my point...HS gauges aren't different in different chambers, the HS stays the same.

I agree with DS and JG...H4350 will work but something slightly faster might be magical. Sometimes we try stuff and it works and other times we try stuff and it doesn't.

Example - I have a decent stock of H4831sc that I used in a 6slr years ago...I thought I'd try it in the 22 Gaymoor w/ 80.5's. It shot a ragged [censored] hole but is only 2980 and that's not fast enough...failure...back to the H4350 to try. It was worth trying...just too damn slow.

Suggestion Buzz - I'd also try some 120's or even lighter bullets in that short of a 6.5 Gaymoor...it's anemic and needsmoor as it is then you start cutting the barrel down and it gets SLOW with a 130/140. My unpopular 2 cents.

Bullet weight may also play a role in what powder you might choose. I like H4350 for the heavies and Varget for lighter 120s or less. I am currently happy pushing 110 Hammer Hunters with Varget in an 18" barrel.

What speed

He won't have the rifle long enough to do load development anyway.

I use R17 in my 260, pushing 120 gr Nosler BTs, but since that seems impossible to get, I may switch to H4350 eventually. For the 100 gr Nosler BTs, I use IMR 4064. I don’t use the 140 gr bullets, wanting to get as close as I can to 3000 fps in my 20” barrel.

For the OP, if you have the rifle long enough, go with H4350.

i dont have it either. thought about it but will stay at 20" for now. going to try the Miricale stock to save weight.

thanks for the answers

JG, yes i do owe yall something practical.

You're right, I misspoke, and thanks for correcting that.

As far as I’m concerned, you don’t need to do anything practical. Just keep buying and selling, having fun, and giving the forum stuff to talk about. Some of the stuff you buy makes us green with envy (that vette for instance).

Superformance is another powder that gives more velocity than H4350. At least in my 6.5 CM, the accuracy is the same between that and H4350.

I get the strange feeling that Judd doesn't like the 6.5 Creedmoor.... LOL

Am I that obvious?

"Superformance", I'm very familiar with this branded name in their factory loaded ammo. They (Hornady) sell the identical powder under the same name?

I've hunted it and shot it on the range to verify zero year round. Been consistent for me.

I see Hodgdon lists it only for 143gr bullets or heavier in the 6.5 Creedmoor so figure it is on the slow side for lighter weight bullets. Just a guess though

My partner hunts with it in 129 GR. SST, Superformance Factory loads. Excellent results as well. Actually been shooting it a couple of years now. This is from a great rifle, 18" Alamo Precision. We shot it two days ago to test the CDS dial just installed. I shoot the factory ammo, 165 gr. .308.

2915 if I recall correctly. Am not pushing it hard. Good groups and cold bore sync at this load.