Alex Wheeler
Site $$ Sponsor
When you change powder or bullet lots you get to start over from scratch and HOPE the barrel likes those new lots as much as the old ones.
Load Development Help - Rifle Went Out of Tune
- Thread starter treillw
- Start date
Sandstorm
Gold $$ Contributor
This seem pretty normal of a problem considering what has ensued up until now.
Not cleaning. changing lot's of powder, bullets etc..etc....yep surprised it took this long to unravel,
Good news is you can get it back with some elbow grease..probly lots of it...lol
and rework your load after cleaning...
Not cleaning. changing lot's of powder, bullets etc..etc....yep surprised it took this long to unravel,
Good news is you can get it back with some elbow grease..probly lots of it...lol
and rework your load after cleaning...
Throw, the Nylon Brush away ! You HAVE,.. Multiple, "Problems" in,.. OUR opinion.
Clean with, Barnes C-10 or, Sweets and use, a .30 Cal. BRONZE, Brush after, a Half Hour "Soak" to get Copper out. NEXT,.. Dry barrel, then use, Eliminator C-4, Carbon remover,.. TWICE if, needed.
IF, a Bronze Brush "hurts", a good Steel Barrel, I'd be, REAL, surprised ( just don't go too "crazy" using, it ! ).
Then do, a NEW, Powder, and Bullet "Ladder Test" as suggested by,.. Ned Lund, INTJ and Alex Wheeler, in Posts,.. 17, 18 and 21.
Clean with, Barnes C-10 or, Sweets and use, a .30 Cal. BRONZE, Brush after, a Half Hour "Soak" to get Copper out. NEXT,.. Dry barrel, then use, Eliminator C-4, Carbon remover,.. TWICE if, needed.
IF, a Bronze Brush "hurts", a good Steel Barrel, I'd be, REAL, surprised ( just don't go too "crazy" using, it ! ).
Then do, a NEW, Powder, and Bullet "Ladder Test" as suggested by,.. Ned Lund, INTJ and Alex Wheeler, in Posts,.. 17, 18 and 21.
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YUP,. "bingo" ^^^
I recommend you acquire a chronograph and do ladder tests with successively increasing charge weights to find a flat spot in muzzle velocity. Calculate your SDs for your existing recipe. It should be 10 fps or less. It is hard to shoot good groups if your velocities are all over the map.
Old Navy
Gold $$ Contributor
Yep! Time to take it down to bare metal and start over.
I'm not a tuning expert (shocker, right?). Can somebody run me through the process a little, or are there other basic threads on this? I have the general idea.
To get my previous half minute load, i just started doing all kinds of systematic random loads in different lengths and charges. Happened to hit one that was half minute and i didn't try to tweak it any further.
My main question on this is what do you consider a load worth investigating/tweaking? Ie do you look for a random load that is half minute or 3/4 minute to start with? What do you do to then tweak and refine that load?
Thanks for the help!
To get my previous half minute load, i just started doing all kinds of systematic random loads in different lengths and charges. Happened to hit one that was half minute and i didn't try to tweak it any further.
My main question on this is what do you consider a load worth investigating/tweaking? Ie do you look for a random load that is half minute or 3/4 minute to start with? What do you do to then tweak and refine that load?
Thanks for the help!
If it were me and trying to minimize the work, lengthen the OAL say 5 thou and try powder loads either side of where you were, say 1/2gr steps either way.
Although like others have proposed finding a good and hopefully wide plateau is the best long term solution so a load is less likely to go out of tune.
3Ackleys
Gold $$ Contributor
How many shots went into half minute? (was it repeatable on multiple targets shot over multiple days) If yes I think after a good cleaning you can probably get there again. Until I bought a bore scope I wasn't coming close to getting my barrels clean.
the problem I run into with option A - testing systematic random loads until one stumbles across a good one is that when your node moves or something goes astray you don’t know where it went or how to get it back.
Option B is actual load development where reaching our node and knowing the width of a charge window or seating window and what the load looks like when we go in and out of tune becomes a bit of diagnostic tree, as posted each new lot number of components like powder needs to be varified in fps and noted, same with bullets where perhaps the pressure ring is different causing seating variations from neck tension Etc. I don’t think taking a barrel to bare metal helps matters rather adds an additional layer of complexity.
Bore tech Eliminator or similar and a few passes with a bronze should be plenty of scrutiny for the moment.
Good luck and please report back
J
^^THIS^^
Did you previously record your action bolt torque settings? If something has loosened, moved, wood stock shifted, etc....you may need to make certain that everything stock/action related is still copacetic?
.
I shot 4 or 5 4 shot groups 200 yards to confirm the load wasn't a random fluke.
Used it for a couple years with no flukes.
In the market for a bore scope.
I have a torque wrench and specs that i always use (manufacturer specs) written down. I've checked them. Synthetic stock. Should be good to go.
Start a new thread
Hengehold
Silver $$ Contributor
Ned Ludd,It looks like the original load (top, left) had one pulled shot out right, otherwise it would still have been about 1/2 MOA. Perhaps the load is still ok and it is the trigger puller that needs some work.
How many rounds have you put through the rifle in the last year? That number should give you some indication of whether it is time to re-visit load development. If it is only a couple hundred rounds, my first observation probably holds true. If the number is closer to 1000, measure the distance to "touching" the lands and see how it compares to the last measurement in terms of COAL or CBTO. If you decide to continue tweaking the load, I would also suggest using a finer increment in seating depth testing like .003". It is sometimes possible to miss a fairly narrow seating depth optimum when using a seating depth test increment as large as .005".
How does the current muzzle velocity compare to what it was when you first worked up the load? Likewise, a noticeable change in velocity due to temperature differences or other sources can also be an indicator that you need to re-visit charge weight as well as seating depth. If so, I'd probably start with that first, and leave the seating depth where it was until you find a [new] optimal charge weight. Then you can re-visit seating depth using the most recent optimal charge weight, and slightly finer increments.
Keeping meticulous records during load development is critical. If you have good records, the rifle will usually tell you whether it is time to re-develop a load. Accuracy/precision is only one indicator that it is time to re-work a load that has been in use for a while. Other indicators such as round count, the distance from bullet to lands (i.e. land erosion), and muzzle velocity can also provide useful clues when something has changed sufficiently to warrant closer inspection and possible load re-development.
Finally, how good are you about cleaning the rifle? Build-up of carbon at the end of the case neck (i.e. "carbon ring", or in the throat and first couple inches of barrel can also do bad things to accuracy/precision. If you don't own a borescope, a good cleaning regimen after every use of the rifle is strongly recommended, so as never to let significant carbon/copper fouling build up in the first place. I'd be cautious about suggesting to everyone that they should run out and buy a borescope. The Teslong borescopes have certainly brought decent quality borescopes into such a low price range that almost anyone can own one if they wish. However, the downside to that is that there is also tendency for new borescope owners to reach a state of high anxiety over every little speck they find in the rifle bore or chamber. I refer to this as "Borescope Anxiety Disorder" (i.e. BAD), and it can sometimes be almost as much a problem as not looking at the bore at all. Nonetheless, it is not a bad idea to have one, even if it is used most often simply to ensure the chosen cleaning regimen is working satisfactorily.
I question your statements about seating depth adjustment in .003” increments. That seems contrary to suggestions by others such as Berger Bullets. A contrary seating depth adjustment method would be to adjust seating depth in larger adjustments, maybe 0.030” to 0.040”.
The idea of adjusting by 0.003” seems odd to me because in the case of a cartridge like a 300 WM that only gets 1k rds out of a barrel, the length of the throat could change by .003” by the time he is done shooting his 100 rds or so during a range session developing loads. If the gun needs to be in a 0.003” window to be in tune then it will likely be out of tune by the end of every match. Just doesn’t make sense to me.
what Bullets are you needing to do this with (tangent, secant, hybrid) and what disciplines are you shooting?
Respectfully,
-Trevor Hengehold
This is the one I bought. Your interface needs may be different.
Fast14riot
Gold $$ Contributor
The Berger test is a gross adjustment to find the potential seating depth that you would then fine tune with .003" steps. Can be used on all bullets.
Either by watching your long range vertical groups to see when shots ease rising or preferably with a chronograph.
Some say listen to the target and really in the end it's the only judge however for a sporting rifle you need know velocities for drop charts unless you're gunna take the trouble to shoot at a multitude of distances and and log all the results.
I know of no one that's keen enough to do that with a 300WM sporter.
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