very confused

[charly hunter]

I am hoping someone on here can shead some light for me. I chronographed my .223 the other day and with a 50gr V-Max seated at sammi spec in a 24" barrel 1-12 twist and 25.2 grs benchmark powder a 3 shot average was 3189 fps. Now a mate was at the range and he asked if I do his for him, he has a .223 24" barrel and using 52gr siera bullet, 25grs benchmark powder and loading to sammi spec his rifle also has a 1-12 twist his 3 shot average was 3398 fps. Other than the bullet being different my case is 20 thou shorter than his. His rifle never had a mod on it so I took mine off which made no differance. As I am using slightly more powder and a lighter bullet and the V-Max has a better BC, in therey mine should be faster. I spoke to Varminter about it and he asked if I had a clean barrel, which I didn't. So yesterday I cleaned and scrubed it went out and did the test again with the same results. Infact it was 21fps slower that through a dirty barrel Can anyone shed some light please.......don't forget you are talking to a dope so writen in plain ideot proof words will be fine fanx

[Elwood]

Charely I can't really help you on the reasons why, but I'm using 26.3 of benchmark (safe in my rifle but a hot load) with a 52 grain Amax and 25 inch barrel and I'm only just hitting the 3400 fps mark.

I would say your friend is lucky getting that from 25 grains, I'm sure some of the guys here will know why.

 

Ian

[Ronin]

Charly

 

 

the plain simple facts are that no two barrels will shoot the same even identical factory guns will be slightly different.

 

Example;

 

I had a standard 25-06 Rem 700, it shot a 100g Speer FBSP with 53g Vit 160 at 3100fps.

 

Had it rebarrelled with a Krieger cut rifled match barrel and with the same load, I now get 3330fps.

 

Every rifles different

[Vermincinerator]

Andy is spot on, there are many factors involved in barrel manufacture between different and like makers.

IMO it all boils down to friction.

Barrels can be hammer forged, button rifled and cut rifled, custom barrels are also lapped and polished.

Then there is the rifling form, number of grooves and lands, width of the grooves etc... all add up to the amount of friction applied to the bullet as it travels up the bore.

 

Ian.

[varminter]

Very interesting and i thought when we spoke Nigel that a good clean would of increased your velocity!!!

Sorry i was wrong Nigel but guns are finicky blooming things!!!!

All i can sugest nigel is to work the load up a bit more ( looking for the pressure signs as always ) and see how much more velocity you can get but also make a note of how the accuracy is ( most important ) ...

If it increases then good job done but if the group opens up then stick to what you got..

Let us know how you get on buddy!!!

All the very best..............

RAY.......................

[Andrew]

Andy and Ian are correct: No two rifles will deliver identical performance, even with identical loads. You're worrying about nothing. ~Andrew

[Guest 308Panther]

Many,many years ago I got into a very interesting discussion

with my service manager about "Hot" loads....

His reasoning back then was that in alot of ways a cartridge and

bullet have alot of similarities to a gasoline internal combustion engine.

Gas engines have an optimum air/fuel mix of about 13- 13.5:1

Again this was his reasoning...and since I am just learning to play with

a couple balcalc progams I havent had a lot of chances to play and confirm this theory.

But his reasoning was that if you back off the powder you increase the amount of air

that is held in the casing and it creates a hotter load.And if you increase the powder

it can create a slower load....

Again....I havent had a chance to prove this,and since its theory I really am not sure what needs to be proved....and to a degree it may have some truth to it....but as to how much does what and to what effect...I cant answer.But it may shed a little light on the subject.

 

I agree that no 2 rifles will shoot the same load with the same results and that it is really nothing to be worried about.

 

 

308Panther

[onehole]

Its probably down to pressure Nigel and the other guys overall chamber could be a tad smaller thus giving a tad more pressure and up goes the velocity.You may find that your load is in fact quite mild for your gun and more can be found by carefully increasing powder charge.Your velocity is down from what I would expect a 223 to be producing with that head on but tke care anyway mate.If its accurate and doing the job perhaps leave it where it is???cheers boy.onehole.

[charly hunter]

Cheers guys, It's not something I am bothered about because as onehole said if it shoot well leave it alone, and it does and I am very happy with the groups.

 

I am only a novice at this reloading buisness although I have been doing it for about 5 years I am not as keen as most of you guys as my rifle is a tool to do a job, I am not as keen as most to shoot long range I am puerly a varminter. That said I know all guns are differant but I weren't sure if it would make that much differance, but you guys are far more knolageable than myself on the subject, so I thought I'd ask the experts. So thanks for enlightening me I knew you wouuldn't let me down.

[Vermincinerator]

Panther,

By the way of modern chemistry, smokeless propellents carry their own oxygen generating constituants just the same as many explosives except there are also built in retarders to stop detenonation.

Because of this powders do not need air to aid with the burning, unlike petrol.

I can see where your friend is coming from, his theory works with IC engines but not with powder, richen up the mixture and it does not burn as efficiently lean it out and it may not burn at all.

Take a look a fuel dragster motor, nitromethane is injected so that when it is burned together with the methanol it creates huge amounts of oxygen resulting in much more violent combustion.

Superchargers and turbochargers do the same by forcing more fuel/air mixture into the combustion chamber.

The same principle applies to the powder except like i said it carries its own oxygen supply.

Therefore more powder means more gas into a given area, createing higher pressure and thus a faster projectile, up to a point.

Thats my outlook on it anyway

 

Ian.

[stag1933]

Hi C.H.

You are not doing a test on a level playing field, different bullet type and weight, different powder charge etc.

Possibly one bullet core is harder than the other.

All these are small details but will make a difference to the end result.

You did not mention brass, were you both using the same as different brass has different internal capacity and this can cause a serious variation.

 

HWH.

[charly hunter]

When I go to the range next I will load my rounds and fire them through his rifle and let you know the results, Stag.

[Guest varmartin]

Dont forget to` full length size` them Nigel, I am sure you knew that , just makin sure.

 

Martin

[Redfox]

Ian has it right more powder more pressure, less powder less pressure, then your into primers, case volume, bullet type and shape, all of which affect the outcome before you get onto rifle differences.

With IC engine it is called the stoichiometric ratio, as you say around 13.5 - 1 now more in the 14-14.5 -1 with lean burn technology, but good old Nitro powder carries it's own oxy bottle so to speak.

Surprising what actually affects the end result when you pull the trigger ( should be squeeze I suppose), but if it was that easy it would be no fun.

Redfox

[charly hunter]

Redfox I don't think you read the whole of my first post pard so I will put the important part here again......" don't forget you are talking to a dope so writen in plain ideot proof words will be fine fanx" You are getting to tecnical for my dumb ass but ta, anyway

[Redfox]

Nah not technical just showin off my big words Lol.

THere are good loads to try in the Nosler and Sierra manuals and dont forget the likes of Hodgdon give load info for cal and bullet weight on their website. The Vhitavuori site has loads but only limited bullet types, but you will soon get the hang of it and find what works in your rifle.

Redfox