6.5 creedmoor velocity loss?

[triceratops3]

I've been putting together a 6.5 creedmoor and its been just about done for a couple months now. but I've been thinking about cutting the barrel down.

Right now it has a 28" criterion barrel on it and is a great rifle but I just got an eberlestock pack to tote it around and It sits a little high up in the pack. So i've thought about chopping it to 24". Then it'll ride in the pack easier and will probably be better balanced as well.

Right now (using jmb and real world drop to 1200 yards) my velocity is about 2820ish fps.


1. Does this velocity seem a bit low for a 28" barrel? (I was looking at the 6.5 creedmoor load data thread and most of the 24"s were running at about my velocity of 2820fps.)

2. How much velocity do you think I can expect to lose? (my loads are 42.6 gr of H4350 @ 2.81" OAL)

I would hope my velocity would stay at or above 2750, think it will happen?

 

[poison123]

Re: 6.5 creedmoor velocity loss?

What bullet?

 

[plt228]

Re: 6.5 creedmoor velocity loss?

I've got a Stevens action and a 23" Benchmark Barrel thats been melonited. The guy I bought it from said it'll do 2830 with factory Hornady 140 amax. I don't have a chrono but so far shooting it the numbers seem to be holding true.

 

[RugerSlinger]

Re: 6.5 creedmoor velocity loss?

You would probably loose about 75fps with a 140gr bullet. I loose about 150 with 9" shorter barrel.

 

[ddavis]

Re: 6.5 creedmoor velocity loss?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: triceratops3</div><div class="ubbcode-body">I've been putting together a 6.5 creedmoor and its been just about done for a couple months now. but I've been thinking about cutting the barrel down.

Right now it has a 28" criterion barrel on it and is a great rifle but I just got an eberlestock pack to tote it around and It sits a little high up in the pack. So i've thought about chopping it to 24". Then it'll ride in the pack easier and will probably be better balanced as well.

Right now (using jmb and real world drop to 1200 yards) my velocity is about 2820ish fps.


1. Does this velocity seem a bit low for a 28" barrel? (I was looking at the 6.5 creedmoor load data thread and most of the 24"s were running at about my velocity of 2820fps.)

2. How much velocity do you think I can expect to lose? (my loads are 42.6 gr of H4350 @ 2.81" OAL)

I would hope my velocity would stay at or above 2750, think it will happen?

</div></div>

My load is also 42.6 of H4350, which is pretty close to the factory loads. Factory loads and my reloads do ~2730 in a 21" barrel. With a 24" barrel, you will probably be close to 2750-2780. I say do it.

 

[triceratops3]

Re: 6.5 creedmoor velocity loss?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Poison123</div><div class="ubbcode-body">What bullet? </div></div>

140 amax's.

I think I could always try a little bit more powder if im not completely satisfied with the velocities.

 

[car2go4]

Re: 6.5 creedmoor velocity loss?

i have a couple CM's and have been shooting them w 140g bullets from the get go. fwiw id drop back to 23-25 from 28. id also be slow to go much under 23" especially if ur running past 600

 

[turbo54]

Re: 6.5 creedmoor velocity loss?

My understanding is CBI barrels are lapped such that the bore constricts a little at the muzzle, which according to theory, promotes accuracy. Cutting it off would eliminate any extra goodness that would give.

Jim Briggs told me about this constriction when I ordered a barrel, and mentioned i might chop it down.

The theory is sound, according to Harold Vaughn's book "rifle accuracy facts"

Take it for what you think it's worth.

 

[Killswitch Engage]

Re: 6.5 creedmoor velocity loss?

i vote for a folder and keep your barrel length. fwiw, i am getting 2860 out of my rock 26" with 42.9 of 4350.

 

[rc2125]

Re: 6.5 creedmoor velocity loss?

6.5 creedmoor: savage LRP 26" barrel, 42.0 H4350 w/140 amax', was around 2805fps @10ft, 8.2mil ~1k (200yd zero).

The same load in my 24" savage Model 10 was running around 2770fps (*if I remember correctly).

Had to sell one or the other, sold the LRP, it was a great range gun, but prefer the shorter 24" rifle for all around use and it sends them supersonic past 1200yds still.

Switched to 139 scenars @2775 w 42gr, 8.2mil 1k w/200yd zero, elev 500ft

 

[triceratops3]

Re: 6.5 creedmoor velocity loss?

Thanks guys I really appreciate the input.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bob2</div><div class="ubbcode-body">i have a couple CM's and have been shooting them w 140g bullets from the get go. fwiw id drop back to 23-25 from 28. id also be slow to go much under 23" especially if ur running past 600 </div></div>

yeah I will be shooting out to about 1000-1200 yards so i dont want to go too short but even if I only get 2700 fps then It should be super sonic to around 1310 yards, which is only 50 yards or so shorter than what it is now.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Killswitch engage</div><div class="ubbcode-body">i vote for a folder and keep your barrel length. fwiw, i am getting 2860 out of my rock 26" with 42.9 of 4350. </div></div>

I wish I could get a folder. I just bought a manners T4a and ever since they came out with the folders I wanted one so I could use a pelican case that would fit in the trunk of a car.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">My understanding is CBI barrels are lapped such that the bore constricts a little at the muzzle, which according to theory, promotes accuracy. Cutting it off would eliminate any extra goodness that would give.

Jim Briggs told me about this constriction when I ordered a barrel, and mentioned i might chop it down.

The theory is sound, according to Harold Vaughn's book "rifle accuracy facts"

Take it for what you think it's worth. </div></div>

I'll have to look into that some more but theoretically, shouldn't a CBI be of better quality than a factory barrel and along with a good crown the barrel should still shoot accurately.

 

[J1Rjr]

Re: 6.5 creedmoor velocity loss?

I have a 308 that factory ammo says 2650 on a 26” barrel and I still get 2650 on my 20” barrel with an aac breakout