Reloader 16 velocity jumps in 6.5 CM

[KingCountry LRS]

I’m trying reloader 16 in my 6.5 creedmoor with 130 Berger hybrid otm projectiles. Hornady brass. My loads during load development are fine but once I start having strings of fire the speeds jump up in speed every shot , sometimes by 10fps per shot. I have a RCBS charge master that’s been accurate on all my other rifles so that’s not the problem.
I have used reloader 16 before and had the same issues, after about 8 shots it jumps up o pressure then disappeared again once I let rifle cool of for a minute.

I find it strange as I’m not leaving the cartridge in the chamber long at all and it’s pretty cold outside so I’m lost as to my the speed always starts climbing.???
Guess my rifle just doesn’t like it!!

my load is just 43.4 grains of reloader 16 doing 2840fps

 

[Pilotscrappy]

That's a pretty hot load .. you haven't had pressure issues with that on your brass ?
For reference when I use rl16 for my 6.5
I'm using 41.6 gr of rl16 in lapua brass @ 2760 fps.
Plenty fast enough for me and I've been shooting at 1400 yards

I would try a lesser charge and use that node
Shooting your current load on hot days could be problematic/dangerous

 

[kriller134]

Yeah I agree that’s a hot load. I’m at 42.6 with a 142smk going 2850. What rifle and barrel length? Seems really slow for a 130 bullet and that much powder.

 

[KingCountry LRS]

The Alliant website puts max charge at 44 grains , they also put the velocity at over 2900fps so I assumed I was way under max already. and no everything is good no pressure even at 44 grains. Tikka ctr with 24 inch barrel.

 

[KingCountry LRS]

I also have a load for my 142 matchings using reloader 16 and I’m sitting 42.5 grains getting 2750fps so now I’m using 130s there’s more case capacity so I would of thought 43.4 would be not to hot for 130s ???

 

[KingCountry LRS]

 

[KingCountry LRS]

 

[KingCountry LRS]

Haha if I used 41.6 grains I’d only get 2680 FPS

 

[TheOfficeT-Rex]

I haven't used hornady cases - but I've never been able to get more than about 42,5gn of 16 under a 130 before pressuring out. I don't own one, but the talk on tikka barrels is they tend to run slow.

When you say speed increases per shot - you mean each successive shot after #8 is +-10 fps faster than the one before? And it's right back to normal after a little cooling? I'd almost lean towards a heat management issue - or a load stability issue. You may want to run it a bit slower and see if you get the same stability issue.

 

[gigamortis]

The Berger 130 hybrid is my favorite 6.5 projectile out of my 24" factory barreled Ruger RPR. My load is 42.6g of RL-16 in Starline brass at 2.800". It runs 2850fps with single digit SDs. Brass life is exceptional. I tried finding a node up above 2900fps, but started getting pressure signs about 2930fps and the groups were getting worse the farther I got past 2870fps. The 42.6gr load in my barrel has a pretty wide accuracy node from 2830-2870fps. With your issues, I would suspect that factory Tikka barrel is the culprit. They tend to run on the slow side compared to other manufacturers barrels.

 

[KingCountry LRS]

Yeah so after only about 3 shots , each shot after that will speed up . The first shot is normally super slow on cold barrel. My last 8 shot string went 2788 - 2820. - 2835. - 2848 - 2850. - 2858 - 2862. - 2860. Then I stop because it starts worrying me. Super strange.
I will drop back a grain and see what happens , but it’s got to be a temp stability issue but only after less then 10 rounds?? My barrel and suppressor are only lukewarm at best!!
It truely has me stumped , like I said not the first time I’ve had this happen with this powder.

 

[AllenOne1]

Are you shooting these single feed or through a magazine. Is it possible you are getting bullet movement from the recoil and it is causing a velocity increase?

 

[KingCountry LRS]

They are in a magazine, never heard of this before, would that have something to do with neck tension?? Being hornady once fired brass they do feel real soft to seat the projectiles

 

[Choid]

I'm using 42.6 and 42.7 under 140 hybrids and getting over 2900 in two different 26" barrels.. I would actually prefer to dial it back , but they shoots so well and so consistently, I can't bring myself to do it.

 

[AllenOne1]

They are in a magazine, never heard of this before, would that have something to do with neck tension?? Being hornady once fired brass they do feel real soft to seat the projectiles

It would be related to neck tension. If your neck tension is super light you might have some issues. But I only run 1.5 thousands of neck tension and have no issues in a 6.5C. Measure your neck diameter before and after seating the bullet and see what you have.

 

[KingCountry LRS]

It would be related to neck tension. If your neck tension is super light you might have some issues. But I only run 1.5 thousands of neck tension and have no issues in a 6.5C. Measure your neck diameter before and after seating the bullet and see what you have.

Okay I’ll check that

 

[TheOfficeT-Rex]

It would be related to neck tension. If your neck tension is super light you might have some issues. But I only run 1.5 thousands of neck tension and have no issues in a 6.5C. Measure your neck diameter before and after seating the bullet and see what you have.

Good thought - make sure you mark where you measured since necks cam vary in thickness. The optimal way to do this is with pin gauges.

If you want to check if its setting your projectiles back - measure the COAL of the first round you put in the magazine, then load the rest. Shoot everything but the last round and re-measure it. I've never experienced any setback, even with a semi-auto, using 2k of neck tension (pin gauge method).

 

[KingCountry LRS]

Okay I’ll check that

So I don’t have digital callipers and being a kiwi I suck at inches, help me out , I’m getting half of the smallest increments on my callipers? Unsized

 

[KingCountry LRS]

This is after sizing

 

[AllenOne1]

Well if you are saying you have 1/2 mm difference between a sized case neck and a loaded case neck that would be about 1.5 thousands of an inch. But I'm not sure that is what you are saying.

 

[KingCountry LRS]

Yeah I’d say

Well if you are saying you have 1/2 mm difference between a sized case neck and a loaded case neck that would be about 1.5 thousands of an inch. But I'm not sure that is what you are saying.

Yeah I’d say I have just touch under 1/2 mm

 

[kriller134]

In my experience Rl16 is very temp stable. How long between shots? Have you cleaned it? Possible carbon ring?

 

[AllenOne1]

Yeah I’d say

Yeah I’d say I have just touch under 1/2 mm

That might be a little on the light side. As suggested above measure your first bullet in the mag fire several on top of it and remeasure to see if you have any movement. Another test would be to single feed them and see if you get the same velocity jump you saw before.

 

[KingCountry LRS]

In my experience Rl16 is very temp stable. How long between shots? Have you cleaned it? Possible carbon ring?

Yeah was cleaned not to long ago, it has to be something to do with temp as the speeds drop once everything is cold again. My experience with carbon build up is once you have it built up pressures will stay the same until you clean it

 

[TheOfficeT-Rex]

It's hard to read those calipers on a computer screen, but I come up with .33mm or .0013" neck tension. That's a little on the light side, How are you sizing your brass? I still don't think that's the issue - but could be something to play with in the future.

Yeah so after only about 3 shots , each shot after that will speed up . The first shot is normally super slow on cold barrel. My last 8 shot string went 2788 - 2820. - 2835. - 2848 - 2850. - 2858 - 2862. - 2860. Then I stop because it starts worrying me. Super strange.
I will drop back a grain and see what happens , but it’s got to be a temp stability issue but only after less then 10 rounds?? My barrel and suppressor are only lukewarm at best!!
It truely has me stumped , like I said not the first time I’ve had this happen with this powder.

Missed this before - Is this string with a cold, clean barrel, or does it replicate each string (after cooling)? If its only the first string, I wouldn't consider that too uncommon.

 

[Joeg26er]

I am going to guess he is getting set back on each bullet after the first which is causing velocity to climb

 

[AllenOne1]

It's hard to read those calipers on a computer screen, but I come up with .33mm or .0013" neck tension. That's a little on the light side, How are you sizing your brass? I still don't think that's the issue - but could be something to play with in the future.



Missed this before - Is this string with a cold, clean barrel, or does it replicate each string (after cooling)? If its only the first string, I wouldn't consider that too uncommon.

Good catch if that is a clean and cold bore running off 4 shots to bring it back to normal would not be that unusual.

 

[KingCountry LRS]

Good catch if that is a clean and cold bore running off 4 shots to bring it back to normal would not be that unusual.

Yes it is off cold bore but not clean.

 

[KingCountry LRS]

That might be a little on the light side. As suggested above measure your first bullet in the mag fire several on top of it and remeasure to see if you have any movement. Another test would be to single feed them and see if you get the same velocity jump you saw before.

So I just got back from doing a heap more testing

I tested the bullets being affected by recoil scenario and that wasn’t the problem, the COAL stayed the same!

I then Dropped my load back to 42.6 grains of 16. The shots went as listed (semi warm barrel not cold). 2794-2810-2814-2808. So it seemed to settle down a bit with lighter load, .6moa group. The ES is average but I don’t have a lot of these projectiles left and being in New Zealand we’re the last people to get things from US trickle down to us so I’m having to change my components a lot to what ever I can find. So I’m not going to be to fussy. Plus our competitions here only go out to 800m most of the time

 

[Bradv86]

Few things to comment.

1. Neck diameter of a fired case compared to a sized case isn't going to tell you your neck tension. I think the guys missed that the comparison is fired vs sized, not sized brass vs bullet seated in the neck

2. Those conversations are not correct. 0.33mm would be 0.013", not 0.0013. This is sort of irrelevant as y'all were checking for neck tension and the measurement of unfired vs sized was being compared.

3. Not sure why y'all are converting when that vernier has inches on it already the top scale is graduate in .001" and the bottom .02mm.a vernier on a screen is hard to be extremely precise with.


Unsized I read .300 or .301"

Sized I read maybe .291" sort of blurry.