6.5 CM can’t get any velocity, opinions please

[bcarico]

So I got the cheap o borescope, pretty cool, I had a nice look around and no real carbon ring, had a little copper, but in the first 2 inches I found 3 spots that looked like someone touched a welder to the inside of the bore, fire cracking just starting to appear like something that would have 400ish rounds.. idk I’m at a loss, will probably take to another smith and do a chamber cast

I may just do a new barrel, idk, need to save some cash for now..

Does your borescope have the capability of taking pictures? If it does posting pictures of the spots you're seeing may help.

 

[ta6ppc]

I just bought the teslong $39 one so it’s pretty basic not super focused I’ll try to get some with my cell phone and post them

 

[Gtscotty]

Those are great velocities for that length of barrel.

The velocities are about in line with what you'd expect from the loads in Alliant and Sierra data minus ~100 fps for the 4" shorter barrel length. I don't get any apparent pressure signs with those loads, however I did run up to 43.5gr RL16 under 140gr ABs, and got occasional stiff bolt lift so I backed off to the next lower node.

I've been happy with it, I have a friend that runs a little faster load out of his 20", but he uses RL17, and I wanted the temp stability of RL16 . I worked up a load and hunted it a bit before chopping it from 22" to 20", predicably it didn't lose much velocity but I did have to work up new loads optimized for the shorter barrel with an extra weight on the end.

It also shoots pretty well for a rifle that weighs in at 7lb 1.1oz with scope, suppressor and sling.


De-rail aside, the OP's rifle is not exhibiting normal Creedmoor behavior, but maybe a smith might be able to straighten it out for him.

 

[Gtscotty]

I just bought the teslong $39 one so it’s pretty basic not super focused I’ll try to get some with my cell phone and post them

You can focus it some, at least enough to account for bore size by spinning the piece on the end that holds the little mirror in and out.

 

[Kracken McGraw]

The velocities are about in line with what you'd expect from the loads in Alliant and Sierra data minus ~100 fps for the 4" shorter barrel length. I don't get any apparent pressure signs with those loads, however I did run up to 43.5gr RL16 under 140gr ABs, and got occasional stiff bolt lift so I backed off to the next lower node.

I've been happy with it, I have a friend that runs a little faster load out of his 20", but he uses RL17, and I wanted the temp stability of RL16 . I worked up a load and hunted it a bit before chopping it from 22" to 20", predicably it didn't lose much velocity but I did have to work up new loads optimized for the shorter barrel with an extra weight on the end.

It also shoots pretty well for a rifle that weighs in at 7lb 1.1oz with scope, suppressor and sling.
View attachment 1210013

De-rail aside, the OP's rifle is not exhibiting normal Creedmoor behavior, but maybe a smith might be able to straighten it out for him.

Thanks to all of you for answering my shorter barrel questions. I apologize to the OP for the derail.

 

[ngb1787]

The velocities are about in line with what you'd expect from the loads in Alliant and Sierra data minus ~100 fps for the 4" shorter barrel length. I don't get any apparent pressure signs with those loads, however I did run up to 43.5gr RL16 under 140gr ABs, and got occasional stiff bolt lift so I backed off to the next lower node.

I've been happy with it, I have a friend that runs a little faster load out of his 20", but he uses RL17, and I wanted the temp stability of RL16 . I worked up a load and hunted it a bit before chopping it from 22" to 20", predicably it didn't lose much velocity but I did have to work up new loads optimized for the shorter barrel with an extra weight on the end.

It also shoots pretty well for a rifle that weighs in at 7lb 1.1oz with scope, suppressor and sling.
View attachment 1210013

De-rail aside, the OP's rifle is not exhibiting normal Creedmoor behavior, but maybe a smith might be able to straighten it out for him

The velocities are about in line with what you'd expect from the loads in Alliant and Sierra data minus ~100 fps for the 4" shorter barrel length. I don't get any apparent pressure signs with those loads, however I did run up to 43.5gr RL16 under 140gr ABs, and got occasional stiff bolt lift so I backed off to the next lower node.

I've been happy with it, I have a friend that runs a little faster load out of his 20", but he uses RL17, and I wanted the temp stability of RL16 . I worked up a load and hunted it a bit before chopping it from 22" to 20", predicably it didn't lose much velocity but I did have to work up new loads optimized for the shorter barrel with an extra weight on the end.

It also shoots pretty well for a rifle that weighs in at 7lb 1.1oz with scope, suppressor and sling.
View attachment 1210013

De-rail aside, the OP's rifle is not exhibiting normal Creedmoor behavior, but maybe a smith might be able to straighten it out for him.

I would normally see about a 25 fps change per 1" of barrel length. Have been running my creedmoor at 30" length and averaging around 2875fps with 40.6 h4350 and 142gr. Can pump that up to 2975 fps with no bolt lift however the groups were not changing from 2875fps, also a light ejector mark on back of case. It does surprise me a bit the 20" barrel will hold velocities that fast but numbers dont lie. Any sign of pressure on your cases? What is your barrel life? How do you think the rl-16 compares to h4350, ur packing more grains in a case than me. Keep up the good work.

 

[ta6ppc]

No apologies needed on the derail, I am liking the discussion and it’s going to influence which barrel I get next because I am thinking of a 30 incher... maybe even a straight 30”

 

[JFrank]

I Have a Remington (blue printed) with a custom barrel 8 twist stainless.. anyways it won’t chamber some factory rounds, they are too long. I have to run a oal of like 2.780 or maybe slightly longer if it’s a super pointy bullet like a vld. The most I can get from it is 2650 running 40.2 grains of H4350 and I get an ejection swipe around that, and that’s using Peterson srp brass

I have some really accurate loads running 42.5 of 4831 but it only goes 2550. I was happy until I recently got a lab radar and started seeing what my speeds are.

I got this rifle from someone second hand, however I know the gunsmith and have had rifles built by them before, what would you do?
I’m at a loss..

While yer waiting on a new barrel.. Make up a load with H4895’ that should get er moving

 

[ta6ppc]

Here’s the throat!

 

[ta6ppc]

Roughly 3-6” in

 

[ta6ppc]

Edge of the chamber where rifling starts the dark crater is the spot that looks like a welder touched off on it.. very hard to get a pic to come out well.

 

[sawcarver]

Ive burned out a 17" pistol barrel running a 140 @2650fps. It killed all kinds of stuff moving that slow and lots of rounds shot at 1k and beyond with it.

 

[boltman13]

My experience is Barrel Length = velocity.
Same load, Berger 140 gr Hybrid, H4350 41.5 grs., CCI BR2, Starline Case
29' Hart 2810 fps
30" Bartline 2835 fps
31" Brux 2865 fps
All excellent accuracy, no pressure signs, same reamer all jumped 0.015"
RAP 22" factory barrel same load except Nosler 140 gr CC, 2673 fps
I know some try and say they get 2900 fps but I don't have the nerve to go there. I got 2, 890 rounds on the Hart barrel and the other ones are going strong.
Good luck.

 

[ta6ppc]

I’ve pretty well given up to get the speed, I just will shoot my accuracy load and be done.. I may try some 107-120 grain stuff once I find a small box to buy.. but overall I am pretty much disappointed in this rifle. It shoots decent at 2550 store bought ammo shoots 1” plus and ends up with ejector swipe.

 

[AccelR8]

Based on your pictures, if I'm interpreting them correctly, you've got virtually no free bore. It looks like your rifling begins just about at the chamber...?

 

[ta6ppc]

Based on your pictures, if I'm interpreting them correctly, you've got virtually no free bore. It looks like your rifling begins just about at the chamber...?

That’s pretty much what I am seeing as well which I kinda knew that from sticking factory loaded ammo and doing my ink trick on bullets.. probably explains why Berger VLD’s shoot so well loaded short at 2.78”

 

[Txhillbilly]

Dump the Peterson brass. It has less capacity than Lapua brass. I tried Peterson when it first came out, and got pressure signs way before where I load my Lapua brass.
I shoot out of a 26" Shilen Select Match barrel using Lapua SRP brass - RL 17 powder - Hornady 143 gr ELD-X bullets. I avg. 2879 fps with this load and it shoots good.

 

[BDman]

As Txhb said, I've run into early pressure signs (as have my friends) with Peterson more than any other brand in a couple of rifles. Excellent brass but I only have one rifle I can use it in and get desired velocity without pressure issues.

 

[ta6ppc]

I have tried star line, hornady, and Peterson brass both the start line and Peterson will take more than the hornady in terms of pressure because the hornady brass has a heck of a ejector swipe at 39.5 of H4350 the max I can go with H4831 is 42.5 with hornady brass as well. The chamber is non-existent and I have zero free bore. Basically have a cool looking 30/30 that shoots long pointy bullets..

 

[Bc'z]

Take it in to your local gunsmith and have it throated longer.
Build a dummy round with a sized piece of brass making sure it fits magazine if applicable