Velocity Increase From Clean to Dirty Barrel.

[neil the plumber]

Firstly, thank you to all who offered advice on accuracy issues with this rifle. The gentleman who pointed me in the direction of a New Zealand shooter, whose book prescribes holding the forend and using the sling where possible, hit the nail on the head. The rifle is very unforgiving if its not held down and tightly. Accuracy is still not brilliant, but its getting there.



Got the old F1 Chrono out to see what my current 6.5mm Creedmoor load was doing out my Merkel K5.
New Lapua brass, with flash holes cleaned, case trimmed and primer pocket depth uniformed.
110grn Eagle, lead free ammo, CCi Primers and 30.5 grn of N150.
Each charged measured on digital scales and all Wilson dies used to uniform the case and seat the bullet head.
90 thou off the lands as advised by the bullet manufacturer.
Ammo temp 6.8 degree C and rifle out the cabinate at 11 degree C. Barrel cleaned and oiled after last outing and put in cabinate. Dry patch through before test firing.
String of velocities as follows. Shot indoors, with light source supplied by chrono manufactrers. Barrel allowed to cool between each shot, and barrel temp taken to keep as close to origional starting point.
2200
2224
2265
2329
2351
2417
2327
2314
2345.

Cleaned and put in cabinate for the night, then this morning same clean and firing protocol. This time
2162
2267
2333.

Question, do barrels get faster as they foul up to a point where they start to heavily foul then slow down again.
Not come across this before, but nothing suprises me with this rifle.
Cheers Neil

 

[jcampbellsmith]

In some rifles the first cold clean bore shot is faster, in others the first cold clean bore shot is slower. Over a period of time you may discern a pattern in how your rifle performs. Similarly the first shot in a cold fouled barrel may or may not be slower than the subsequent shots. Getting to the bottom of issues like these is tricky unless you chrono every shot. In an ideal world I would chrono every shot.
Regards
JCS

 

[Andyquadra]

Could it be as the action and barrel warm up, so are the subsequent rounds and so are a little faster?

 

[Sako6.5x55]

Do you think those speeds are fast enough for a 6.5 creedmoor?

 

[Dave_45]

Is there a specific reason you are loading the bullets to that speed?

 

[Andyquadra]

Do you think those speeds are fast enough for a 6.5 creedmoor?

Not sore copper bullets!

 

[Edinburgh Rifles]

With an ES of 200fps or more in the low 2k range I wouldn’t draw any conclusions from it
But it may explain “accuracy issues”

 

[Sako6.5x55]

Not sore copper bullets!

Sako blade 120g non toxic, you would expect 110g to be faster but not with N150. One thing is for sure - it’s not legal for deer.

 

[Cottis]

I recall your thread about accuracy. I was one of the people who suggested holding the forend and controlling the rifle more and I expect someone suggested Nathan Foster who knows what he is on about. Glad to hear some alterations in technique has helped somewhat.

Looking at your velocities, whilst absolute tight numbers are not needed for shooting deer out to sensible ranges, your numbers are showing extreme variations that are not desirable in any way. The very best match shooters might be looking for overall extreme spreads of less than 10fps over many shots. That is not needed for most of our purposes but sound hand loading with half decent brass, consistent charge weights and decent brass prep should see spreads certainly well under 50fps.

I am not familiar with the Eagle bullet personally but I understand it performs well from a terminal point of view at very low speeds and that there might be a tendency to load it down. I am not sure how that might impact your loads ability consistency wise. Yes barrels can show higher or lower speeds depending on cleanliness or dirtyness but in my experience, only to a point. I would expect to certainly see a small difference between a totally clean bore and one that is fouled somewhat but it should settle down after a coupla three shots. Your load is showing some vast variations which I don't know exactly why but I would potentially attribute to the fact that you have so little powder in the case with this particular bullet. I could easily be wrong but you are maybe somewhere in the region of 10grains short of power for a decent case fill. That is not to say many cartridges do not perform fine with underfill. Again, I am not familiar with N150 but I do shoot a 6.5CM and it works best, for me anyway, with decent case fill.

I would say your velocity differences and probably to some degree, your issues with accuracy, are down to the inconsistencies you are seeing from this load.

Is there any reason why you are loading the bullet to such slow speeds? Some of those numbers you posted would not make 1750ft lbs of energy.

My next step would be to get at least 37grains (preferably more) in the case and get the speeds north of 2600fps and I would not be surprised if you started to see velocity settle down and also accuracy to become easier to attain. Unless of course the bullet manufacturer is saying not to load the bullet that fast but that would seem odd for a bullet designed to fragment heavily. I might be talking bunkum but maybe some things to consider. Best of luck with it.

 

[RCS Deer Management]

You are going to experience a lot of runners on deer shooting non toxic that slow. Also as a side note I don’t think that the old f1 chronis are worth a dime, they often produce completely fictional readings. If you can’t trust the data, is the data worth having?

 

[Sako6.5x55]

I recall your thread about accuracy. I was one of the people who suggested holding the forend and controlling the rifle more and I expect someone suggested Nathan Foster who knows what he is on about. Glad to hear some alterations in technique has helped somewhat.

Looking at your velocities, whilst absolute tight numbers are not needed for shooting deer out to sensible ranges, your numbers are showing extreme variations that are not desirable in any way. The very best match shooters might be looking for overall extreme spreads of less than 10fps over many shots. That is not needed for most of our purposes but sound hand loading with half decent brass, consistent charge weights and decent brass prep should see spreads certainly well under 50fps.

I am not familiar with the Eagle bullet personally but I understand it performs well from a terminal point of view at very low speeds and that there might be a tendency to load it down. I am not sure how that might impact your loads ability consistency wise. Yes barrels can show higher or lower speeds depending on cleanliness or dirtyness but in my experience, only to a point. I would expect to certainly see a small difference between a totally clean bore and one that is fouled somewhat but it should settle down after a coupla three shots. Your load is showing some vast variations which I don't know exactly why but I would potentially attribute to the fact that you have so little powder in the case with this particular bullet. I could easily be wrong but you are maybe somewhere in the region of 10grains short of power for a decent case fill. That is not to say many cartridges do not perform fine with underfill. Again, I am not familiar with N150 but I do shoot a 6.5CM and it works best, for me anyway, with decent case fill.

I would say your velocity differences and probably to some degree, your issues with accuracy, are down to the inconsistencies you are seeing from this load.

Is there any reason why you are loading the bullet to such slow speeds? Some of those numbers you posted would not make 1750ft lbs of energy.

My next step would be to get at least 37grains (preferably more) in the case and get the speeds north of 2600fps and I would not be surprised if you started to see velocity settle down and also accuracy to become easier to attain. Unless of course the bullet manufacturer is saying not to load the bullet that fast but that would seem odd for a bullet designed to fragment heavily. I might be talking bunkum but maybe some things to consider. Best of luck with it.

With N150 at 37 grains he’s not likely to achieve 2600ft/s and will still possibly only be around 1500ft/lbs.

 

[Mungo]

Firstly, thank you to all who offered advice on accuracy issues with this rifle. The gentleman who pointed me in the direction of a New Zealand shooter, whose book prescribes holding the forend and using the sling where possible, hit the nail on the head. The rifle is very unforgiving if its not held down and tightly. Accuracy is still not brilliant, but its getting there.



Got the old F1 Chrono out to see what my current 6.5mm Creedmoor load was doing out my Merkel K5.
New Lapua brass, with flash holes cleaned, case trimmed and primer pocket depth uniformed.
110grn Eagle, lead free ammo, CCi Primers and 30.5 grn of N150.
Each charged measured on digital scales and all Wilson dies used to uniform the case and seat the bullet head.
90 thou off the lands as advised by the bullet manufacturer.
Ammo temp 6.8 degree C and rifle out the cabinate at 11 degree C. Barrel cleaned and oiled after last outing and put in cabinate. Dry patch through before test firing.
String of velocities as follows. Shot indoors, with light source supplied by chrono manufactrers. Barrel allowed to cool between each shot, and barrel temp taken to keep as close to origional starting point.
2200
2224
2265
2329
2351
2417
2327
2314
2345.

Cleaned and put in cabinate for the night, then this morning same clean and firing protocol. This time
2162
2267
2333.

Question, do barrels get faster as they foul up to a point where they start to heavily foul then slow down again.
Not come across this before, but nothing suprises me with this rifle.
Cheers Neil

Those are extremely low speeds for a Creedmoor. I think it’s very likely that the really very big variation you’re seeing in speeds from shot to shot have something to do with such low speed. You should really be aiming for at least 2550fps, and actually quite a lot more. With a 110gr bullet, I think you should be getting around 2800-2850.

What lead you to choose that charge?

 

[Mungo]

Do you think those speeds are fast enough for a 6.5 creedmoor?

No!! Not at all!

I think this is the root of his problems.

 

[NullMac]

Dont believe anything an F1 Crony tells you

 

[neil the plumber]

Many many thanks to you all for the input. Greatly appreciated.
I was trying to run the rifle with minimal published loads in an attempt to improve how the rifle shot, as I thought that the recoil on such a light rifle was affecting how I performed behind it.
On previous posts, I mentioned that I was trying everything possible to get the bugger to shoot, recoil being one area to be addressed. With the lighter loads I did get an improvement in accuracy, but this may of been down to my better shooting technique.

I am back on it this morning. I put the rifle away without cleaning, so will see what it starts off with. The rifle is stored in an internal room, so should not be too cold, but the ammo is store in a separate area and considerably colder. Just for extra info.

The last shot of the day was a 123grn SST with 34grn of N140 that gave 2673fps. Will try a string of these today.

Will look at putting some faster rounds together, and see if I can tighten up the velocity.

Might look at purchasing a MagnetoSpeed V3, to help in my quest to get this bugger to shoot.

 

[Cottis]

With N150 at 37 grains he’s not likely to achieve 2600ft/s and will still possibly only be around 1500ft/lbs.

That is true but the point I was trying to make is that he needs to up the velocity which I think will reduce extreme spread and most likely improve the other issues he was having. I did say "preferably more" but baby steps for people who seem intent on loading so light ha ha ha.

 

[Mungo]

Many many thanks to you all for the input. Greatly appreciated.
I was trying to run the rifle with minimal published loads in an attempt to improve how the rifle shot, as I thought that the recoil on such a light rifle was affecting how I performed behind it.
On previous posts, I mentioned that I was trying everything possible to get the bugger to shoot, recoil being one area to be addressed. With the lighter loads I did get an improvement in accuracy, but this may of been down to my better shooting technique.

I am back on it this morning. I put the rifle away without cleaning, so will see what it starts off with. The rifle is stored in an internal room, so should not be too cold, but the ammo is store in a separate area and considerably colder. Just for extra info.

The last shot of the day was a 123grn SST with 34grn of N140 that gave 2673fps. Will try a string of these today.

Will look at putting some faster rounds together, and see if I can tighten up the velocity.

You won’t notice a huge amount of change in recoil by changing the velocity - certainly not enough to really affect your accuracy if your technique is good and you have a moderator.

Get the speed up! At those speeds, the bullet may well not be stabilising very well.

I’d suggest looking at what the bullet manufacturers recommend as the best speed for each bullet, then using something like Quickload to find out what charge you need to get there.

 

[DavyG]

Many many thanks to you all for the input. Greatly appreciated.
I was trying to run the rifle with minimal published loads in an attempt to improve how the rifle shot, as I thought that the recoil on such a light rifle was affecting how I performed behind it.
On previous posts, I mentioned that I was trying everything possible to get the bugger to shoot, recoil being one area to be addressed. With the lighter loads I did get an improvement in accuracy, but this may of been down to my better shooting technique.

I am back on it this morning. I put the rifle away without cleaning, so will see what it starts off with. The rifle is stored in an internal room, so should not be too cold, but the ammo is store in a separate area and considerably colder. Just for extra info.

The last shot of the day was a 123grn SST with 34grn of N140 that gave 2673fps. Will try a string of these today.

Will look at putting some faster rounds together, and see if I can tighten up the velocity.

Might look at purchasing a MagnetoSpeed V3, to help in my quest to get this bugger to shoot.

I doubt that it’s your V3 that’s the issue. IMHO there’s nothing that a generous influx of powder wouldn’t cure.
With N140 you’re going to struggle to get the results that you seek. Personally I’d get a tub of N555, start just below the Viht max and work up from there.
I load for several rifles using Viht powders and have found their figures to be a tad on the conservative side.
However, this works for me but there are many variables to consider. Not every rifle/brass/powder/bullet/primer is the same.
Regards,
DG

 

[neil the plumber]

All good points raised lads, and again thank you for the input.
Will have a look at my powder choice and charge. Will also drop a line to the lads who make the bullets, and ask for any of their recommendations.
Cheers Lads.

 

[plumber01]

As above go a lot quicker, just below max on viht chart, and you will almost certainly find you will be asking questions of what Viht are doing to get the speeds they claim, with that set charge of powder, as they always seem lower when tested ( typically about 5% or so)
N550 or N555 is probably the way to go.
As to the original post about cleaning, its very common for a rifle to shoot differently after cleaning, many barrels need a fine coat of copper on them which acts as a lubricant, so if you clean thoroughly, you are possibly removing this, and until it builds up again, you wont have consistency.
Many people who do a lot a range work will only give the rifle a light brush and pull a boresnake through it after each outing, then after several hundred rounds, give it a proper deep clean, so light clean each outing and every 400/500 rounds ( bearing in mind you might fire 70 to 100 rounds in a day,) so every 3rd or 4th outing clean thoroughly.
This tends to make some shooters believe that cleaning screws up accuracy, (usually the dirtier the rifle the more cleaning will change the point of aim) especially with rimfire, and this makes shooters, particularly hunters who dont fire many rounds , think cleaning unnecessary!
Ask any gunsmith what the average rimfire looks like on close inspection and they might start twisting their faces up, and remind you rimfire ammo is usually the most "coated" and grease covered ammo you can buy etc etc, and hand out a good lecture !
Good luck.