Accuracy at slower speeds

[robbor]

Is there a way to increase the potential of optimum accuracy at slower bullet speeds.
Would having the barrel with say an inch or 2 more twist allow to reduce the velocity like 600-800 fps and still get optimal accuracy roughly? Usually my factory guns are more accurate pushed pretty fast and id really like something quiet and accurate.

 

[Kenny474]

I think the reason you need to push the velocity a bit is due to the barrel, cartridge or even the powder having a preference of higher pressure, and likely is not related to twist rate unless you are running bullets on the ragged edge of stability for the twist rate.

If you are sufficiently stabilizing the bullet at lower velocity in the twist rate you have, it may be possible to find an accuracy node at a lower velocity. Though you may need to change powder to maintain peak pressure or to find a pressure curve that will work at a lower velocity.

If you want to slow things down a bit, you may want to look at a smaller round so you can run slower and still maintain optimal operating pressure.

What are you using for a cartridge and twist rate currently?

You may want to figure the SG of the bullet at the velocity you are currently using and see if it is being sufficiently stabilized, and if it is, would it still be stabilized at a slower speed in the same twist rate?.

I am far from an expert in this matter, so I am sure there are others that can help you more. These are only my thoughts and are not a definite by any means.

Stability calculator: http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi

 

[Scott Harris]

I've heard Sierra does a lot of their accuracy testing at speeds several hundred fps below max. I'm sure you could get some awesome groups and lower speeds....well with non-vlds at least.

 

[bozo699]

robbor,
Were you asking if you can get a gun to shoot accuratly @ 600-800fps or were you asking if you can reduce a load by 600-800 fps and still have it accurate?
Wayne.

 

[robbor]

reduced by 600-800 fps so like in the 2500-3000fps range.
At one time i tried slowing down my 22-250 with lil gun , capacity was to great, To easy to double charge and never see it, never got great accuracy at all. Wondering if id be better off loading a down a 222 or just going to a fireball, just with both had more of an improved case design. Probably could have shot better if i had a lil more twist in the barrel.
Really thinging about the 221 firebal or ,20 vartarg, need a 221 vartarg

 

[Kenny474]

The .222 is a great round. It has excellent accuracy potential, and can even be pushed to match or slightly exceed factory loaded .223 velocities if you want and your action can handle it, yet can be dialed back a bit with great accuracy. The long neck also offers a bit of flexibility in bullet choice, as you can seat the longer stuff deep in the neck, and hang the shorter stuff out a bit and still hit the lands.

I have a .222 with a 1-9 twist and it will shoot most bullets up to 65grs very well, and will even shoot the 70gr Berger's as well. It has little recoil and the barrel life seems to be great thus far, as it hasn't lost much more than maybe a thou or two of throat at I believe 1600 rounds or so, maybe more as I would have to add up what I have written down.

 

[Joe O]

Might try Trail Boss loads.In most cartridges a case full won't cause a dangerous situation.Check with Hodgdon load data.

 

[Nodak7mm]

Just an observation I have noted while developing reduced loads for my girls in deer rifles is that it is incredible some of the groups I could shoot at speeds of 2000 fps.. Easy 1/2" groups outta factory rifles.. Lot to be said about vibrations & recoil affecting accuracy.
Rod

 

[4xforfun]

Isn't there a saftey issue when using reduced loads. I know I hear educated loader/shooters talk about "secondary explosion".

Just wondering.

 

[Kenny474]

I believe the danger with reduced loads is when very slow powders are reduced by extreme amounts. There are certain powders that I believe are more suited to reduced loads than others, and you should always check a load manual of some type before you start reducing loads by more than 20%.

For instance, I know that you are able to reduce loads in a 30-06 by a good margin when you are using H4895, as I have data for it in my manual and have even done a little work with reduced loads with that powder.

Anyway, Modern Reloading states the secondary explosion phenomenon is very rare and usually only results from extreme reduction of very slow powders.

 

[RonAKA]

Hodgdon says you can reduce H4895 loads 60% from maximum, and have published a guide for youth loads.

http://www.hodgdon.com/PDF/Youth%20Loads.pdf

Don't try this with H4831. I loaded some just to the minimum recommended by Hodgdon and got this effect:

 

[bozo699]

RonAKA,
I remember when you posted these pic's. There were many speculations on what had happened. Is that what you came up with for a final conclusion, the loads were just to lightly loaded?
Wayne.

 

[bozo699]

robbor,
I remember a few years ago my Dad was haveing some pest problems where he lives,(in town) I loaded up some loads for my 22-250AI I don't remember the load but it was pistol powder Unique I think just a few grains topped off with cream of wheat, Yes cream of wheat cereal. The loads were sub-sonic and extremly accurate.
Wayne.

 

[RonAKA]

RonAKA,
I remember when you posted these pic's. There were many speculations on what had happened. Is that what you came up with for a final conclusion, the loads were just to lightly loaded?
Wayne.

There is no doubt in my mind that they were too lightly loaded, and there was the mysterious secondary explosion effect. The neck did not seal, and somehow the pressure on the outside of the case ended up higher than inside. One I sacrificed as an OAL gauge, and the other two after being fired with a near max load are back to normal and in faithful service. Dent is gone.

I'm convinced the risk of too light of loads with slow powder is a real one.

 

[bozo699]

RonAKA,
I am not trying to steal robbors thread but now that you know for sure what caused those dent's you might consider posting another thread on the subject as a safety thing. I think sometimes people take there reloading to lightly and stray away from the manufacturer's suguested loads,usually to the high side but you could show how devastating it could be when loaded to low. anyway just a thought.
Wayne.

 

[hogan]

If you're looking for "light-load accuracy" I would give cast bullets a try.

A .30-06 with 180 or 200gr cast bullet of an accuracy design should give you all you are searching for, including almost perpetual lifespan for your barrel. Bound to be the same for any magnum also. Low velocities tend to involve light powder loads and therefore not burn throats and cast bullet of any but the hardest alloy will not wear your barrel.

NEI, Lyman, RCBS, and Redding/SACCO all have many offerings to peruse, or get NEI to make exactly what you envision...