So starting off this I am fairly new to reloading for rifles. Have reloaded alot of pistol and shotgun. I have a Rem 700 SPS in 243win that I have been working up loads for. This rifle was only a mediocre shooter in its factory condition. 1 1/2 moa with most factory ammo and maybe 1 moa with some that it liked. I switched out the stock for a bergara hmr stock inletted for the Rem 700 and skim bedded the action and recoil lug and left the barrel free floating. So got all set up to reload and chose the 95gr SMK to start with over H4350 with FGMM primers and once fired hornady brass. Started out with a 300yrd ladder test in .5gr increments loaded at mag length 2.800 with about .150 of jump. The ladder test showed 41.5-42.0gr and 42.5-43.0gr had promise. So loaded up 41.5-43.0gr in .5gr steps for shooting groups. Once again most where around 1-1.5 moa at 100yrds. Not sure how to continue but not satisfied with results I loaded up 42.0 and 42.3gr but this time started .020 off the lands and worked back in .020 until I had .080 of jump. Wow the groups finally improved. 42.3 at .020 off the lands at .5 moa but the groups open back up at 0.80 jump. Only problem is the best shooters are way over mag length. So where to go from here? Do I continue backing off the lands until something else shoots well? Go all the way back to the drawing board and change to diffrent bullets or powders? I know some bullets tend to like more jump than others. I do have plans to rebarrel the rifle in the not too distant future but would like to use the remaining barrel life here to learn about reloading. Any help would be greatly appreciated.
- Thread starter Ridenemwild
- Start date
No havent tried any other components. This being the first rifle I have ever loaded for was just trying to keep the recipe fairly simple and trying to get all the techniques down. With how the barrel shoots factory loads a rebarrel is definitely in the future but was kinda crossing my fingers that this might shoot well enough to justify keeping it for 6-700 more rounds. It would also allow me to learn on the reloading side before run ing the risk of screwing up a new barrel.
Few things. Working back in .020 increments can skip some seating depth nodes.
Run it over chrono with .020 jump on everything and find a powder node. Then work your way back in .003-.005 increments. Keep going until it tightens up.
If you start going too far back into the case, and the barrel has enough rounds on it that it shouldn’t be doing anything odd like speeding up, it’s probably just not going to be a good barrel.
Regardless of charge weight, you should be able to get acceptable groups via seating depth as long as you’re not skipping seating nodes. You may end up with some unusually long jump, but it should tighten up if it’s not a dud barrel.
Run it over chrono with .020 jump on everything and find a powder node. Then work your way back in .003-.005 increments. Keep going until it tightens up.
If you start going too far back into the case, and the barrel has enough rounds on it that it shouldn’t be doing anything odd like speeding up, it’s probably just not going to be a good barrel.
Regardless of charge weight, you should be able to get acceptable groups via seating depth as long as you’re not skipping seating nodes. You may end up with some unusually long jump, but it should tighten up if it’s not a dud barrel.
But yes. Keep backing up the depth until it shoots or you’re too deep into the casing.
So at 42.3gr and .020 of jump it shot .5moa which is perfectly acceptable to me. But it is too long for the mag. I have to back out until atleast .080 jump for the magazine to even have a chance at working but this is also where the groups started opening back up. Is there even a chance it will shoot well with .100+ jump? Also all shots have been over a chrono and the best groups tend to be around 3125fps which i know is alittle hot but not showing anymore pressure signs than factory ammo.
No need to correlate velocity with group size. Group is going to be harmonically linked with barrel and can be tuned via seating depth.
And yes, there are people jumping .100-.200
Your groups opened back up at .080 and will shrink again as you move back.
Ok. So would .010 steps back be small enough?
You can try it. But I typically run .003 increments.
With .003 increments how many steps does it take to typically see a change? Hard to justify using 30 bullets to move .030 if there arent atleast a node or 2 in there. Not trying to argue, just trying to learn and understand.
You should see something. For example I’ll using see a node between .020-.050. Then groups will get larger and then smaller again after.
Imagine a sound wave. Up and down. That’s how it works.
Ok I understand what you are saying. The reason I chose .020 steps is from bergers recommendations on their vld bullets. At starting .020 of jump and working out from there in .020 steps. I thought this was more of a standard practice. Will definitely try some smaller steps tomorrow.
The Berger VLDs seem to be a special animal - notoriously tough to dial in seating depth with. The info on their web site is directed specifically toward those. I got lucky with my 6CM and found a seating depth node fairly easily. Not so much with my 6 BRA. I just use their hybrids, which are much more tolerant to seating depth.
My experience with the VLD’s is get pretty cozy with the lands or jump them a ton.
Middle ground always gave me meh results.
Hybrids don’t seem to care much.
I don’t go Gnats ass on jump test.
Much rougher increments than DT.
My main concern is vertical dispersion.
For me good bullets and Barrels have always grouped well enough without much fuss.
A factory 243 is going to be throated for lowish BC hunting bullets and Remington is famous for long throats anyways.
Long nosed high BC bullets end up being too long for many magazines when your close to the lands.
long AI mags and a feed ramp notch or a chamber with less freebore are the fix.
here’s a classic example of chamber design.
Saami 7 saum chamber, considered a SA cartridge designed for hunting like your 243.
A 168 classic hunter is 2.860ish on the lands, easily fits SA mags.
a 190 hybrid( long nose and high BC) is about 3.090ish on the lands In a brand new chamber, no way that’s fitting in a SA mag.
you could make the freebore shorter but that would cut powder capacity, best scenario is a long action.
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So going forward in the future should I tend to look at diffrent bullets? I kinda hoped the 95smk was middle of the road for 243. Not a varmint bullet but not a true long range heavy bullet. Would something like an 87gr vmax be a good option? Was really hoping to try some 95 bergers next but this has got me questioning things.
Try jumping them more.
I wouldn’t be surprised if even with super short nosed bullets you might have mage length issues to be close to lands.
Remington 700 are famous for it.
People have been getting good results jumping a ton with them for decades.
In my 260 FGMM with 142SMK’s jumps over an 1/8 of an inch and shoots awesome( I have a special long throat chamber).
Will do. Loaded up test groups at 42.3gr starting at .085 jump working up to .115 in .005 increments. Will see how they shoot tomorrow and report back. These should work though the mag even though they are alittle longer than 2.800 COAL
Well got out and shot this morning. Kinda warm but very little wind. Got settled in and just like yall told me. Started out with big groups and slowly worked its way into some acceptable groups. Good news is all rounds functioned perfectly through the magazine. Some of the SD numbers where alittle crazy but I definitely think 0.59 moa with 10.58 SD at .100 jump is something I can be happy with unless yall see something thats makes me want more lol. Now just need to load a couple of 5 shot groups and start streching her legs alittle to make sure it holds together at distance. I have a fl resizing die that should be here Tuesday and some new brass. Since I have only been neck sizing so far, do I need to totally start over for the first fireing or is this still a decent place to start? Was kinda thinking that I might drop the powder charge .3gr and load at the Ogive number to start out.
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The only reason it won’t hold at distance (if you have good ES and such) is if it’s you not shooting well, or the bullet BC is inconsistent from bullet to bullet.
All the other variables have already been accounted for at 100yds.
All the other variables have already been accounted for at 100yds.
If you want better accuracy, you may tune around where you found the better groups, with .003" variation. It seems to be you can find very stable nodes as you move farther away from the lands, with groups shrinking and growing as you move out. I recently started to find load length by starting at .020 off, and loading one round for every .005" out. Similar to the SAC test, and looking for 3 rounds that shoot in the same poi. It seems like a small sample to have only 1 round at each length, but when I find 3 in the same poi, it seems to be a very stable load length. I don't have alot of data yet, but my groups seem to be holding up. These locations are anywhere from .060" off to .150" off. I have not found any in the .020 range, which is where traditional accuracy is said to exist.
Good article below (and another related linked article on the Hornady 147gr ELD-M). Of course, all barrels and bullets are going to act differently. Also, don’t forget about barrel wear…lans are going to erode +/- 5 thousands per 100 rounds fired through them, which definitely changes your jump calculations.
precisionrifleblog.com
Bullet Jump: Is Less Always Better?
About 2 years ago, Mark Gordon shared some preliminary research he’d conducted with the Applied Bal...
precisionrifleblog.com The OP was last seen Apr 6, 2021…. You could be talking to aGood article below (and another related linked article on the Hornady 147gr ELD-M). Of course, all barrels and bullets are going to act differently. Also, don’t forget about barrel wear…lans are going to erode +/- 5 thousands per 100 rounds fired through them, which definitely changes your jump calculations.
Bullet Jump: Is Less Always Better?
About 2 years ago, Mark Gordon shared some preliminary research he’d conducted with the Applied Bal...
Yes, that's a good article and one that I've given as a reference. However, the one bone I have to pick with it is its constant reference to "bullet jump" when they're really talking about seating depth. It's changes in seating depth that makes the significant difference. And of course, when you change seating depth, you're changing bullet jump. But if the bullet jump changes as the throat erodes, why does accuracy/precision remain for a long time, like many top competitive shooters do by never changing seating depth for the life of their barrel.Good article below (and another related linked article on the Hornady 147gr ELD-M). Of course, all barrels and bullets are going to act differently. Also, don’t forget about barrel wear…lans are going to erode +/- 5 thousands per 100 rounds fired through them, which definitely changes your jump calculations.
Bullet Jump: Is Less Always Better?
About 2 years ago, Mark Gordon shared some preliminary research he’d conducted with the Applied Bal...
I decided to test this with my .308 and kept the same seating depth for a hair over 2,000 rounds and sure enough, it had kept shoot small groups even though the throat had eroded by a little over .030". Given that, why am I not having to "chase the lands" to maintain good performance. It's because seating depth is the primary factor and bullet jump is a very small factor if any; unless of course one is seating their bullets into the lands.
In trying to understand what happens when one is seated into the lands vs a bullet jump and why one can be more consistent than the other, one needs to understand the effects of the blowby as the bullet starts to move and the case neck begins to expand. Note too how the blowby at certain distances from the lands actually reduces velocity as the seating depth increases.
Internal ballistics is complicated.
The other thing that's been proven incorrect is any flat spots one sees with any velocity ladder test. It's easily proven by repeating the ladder test. If should get the same results it's a viable test. But what happens when you do multiple ladders with the same load and when put together you get a linear line.
