Advice - COAL for 280 Mdl 70

[Prerylyon]

Need some advice:

-Working up a load using 145 gr Speer BTSP
-280 REM
- 57 gr of RL-19 (yeah, its max)
-used Speer manual COAL of 3.180" to get 2,845 fps, no pressure signs
-22" bbl
-1980s vintage model 70 featherweight
-measured rifle max COAL with this bullet at the lands is 3.330"

Seeking input on some COALs to try with this loading; am thinking moving 30 mils off 3.330" and then taking 5 mil steps up to 15 mils off the lands.

Thoughts? [emoji2]

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[JimP]

For me there is no real COAL except for what will fit into the magazine or clip of the rifle and what shoots the best. Some rifles like the bullets seated deep far off the lands and others like the bullet almost touching them

I have a .22-250 that you can pull the bullets out with your fingers they are seated so far out but then the rifle is a single shot so I don't have to worry too much about it.

 

[Colorado Cowboy]

JimP is right....every rifle is different. You'll just have to experiment and find what works best.

 

[7mag]

I just loaded a bunch of 140 gr accubonds last night for the exact same rifle. 3.290" is what it likes

 

[Slugz]

Jim and CC summed it up. When handloading each rifle is vastly different then change the bullet and more change is induced. My same Rem 700 shoots Accubonds and Partitions well with two different COAL. I've found the Speer bullets very forgiving, Accubonds want alot of jump into the lands and the Partitions I can load to the max that fits in the magazine.

 

[Prerylyon]

So guys, don't take this the wrong way-I get the rifle/bullet/pwdr personality aspect to this-hence all my specific info that was listed-was curious if anyone had any data with my specific gun and similar bullets/RL19 they might be willing to share.

I hope to get to the range yet this week and see what results I get varying COAL. I will post an update. We went last week and I was happy with the speed-the groups were not as good as I would like at 100 yrds. The 57 gr charge had the tightest group of the charges I tried.

Someday when my life is less hectic, I will have more opportunities to experiment with all this stuff and get to the range more often.

Regards,

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[Colorado Cowboy]

So guys, don't take this the wrong way-I get the rifle/bullet/pwdr personality aspect to this-hence all my specific info that was listed-was curious if anyone had any data with my specific gun and similar bullets/RL19 they might be willing to share.

I hope to get to the range yet this week and see what results I get varying COAL. I will post an update. We went last week and I was happy with the speed-the groups were not as good as I would like at 100 yrds. The 57 gr charge had the tightest group of the charges I tried.

Someday when my life is less hectic, I will have more opportunities to experiment with all this stuff and get to the range more often.

Regards,

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What grain break are you using for the loads you are trying? I use .5 (1/2 gr) difference. eg. 56.5 gr; 57; 57.5, etc. I find sometimes 1/2 grain (more or less ) difference in the powder charge can make a big difference, you just have to find the sweet spot by trial & error.

 

[JimP]

When I am first building up a load I look like I am headed out on a 2 month trip when I head to the range. Not only do I have my rifle and rounds I'll also take my cleaning kit along to clean the barrel between different loading's and like CC I usually go in 1/2 grain increments until I start to see pressure signs or I hit the velocity and accuracy that I want out of the load.

Then if I really want to play around I'll go up only 1/10 of a grain. Then once I find the most accurate load with the velocity that I want I'll play around with the seating depth at the range. I have a few old Lee Loaders hand held loading tools that I can do this with.

A few years ago I spent close to 8 hours at the range just getting a load just right out of one rifle.

 

[Colorado Cowboy]

Yep...me too. I took me several months playing around with all the variables when I started loading for my .257 & .300 Wbys. Being retired helps, having a good shop & lots of experience loading doesn't hurt either. Both calibers were a challenge for sure.

 

[Prerylyon]

What grain break are you using for the loads you are trying? I use .5 (1/2 gr) difference. eg. 56.5 gr; 57; 57.5, etc. I find sometimes 1/2 grain (more or less ) difference in the powder charge can make a big difference, you just have to find the sweet spot by trial & error.

CC,

We tested:

55.5, 56.0, 56.5, 57.0

57 grouped the best and was fastest. Its also max load in the recipe. COAL was very short, at 3.180", which makes me think I should try get closer to the rifle's COAL which, coincidentally, matches the SAAMI max COAL spec for the caliber @ 3.330".

Regards,

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[Colorado Cowboy]

CC,

We tested:

55.5, 56.0, 56.5, 57.0

57 grouped the best and was fastest. Its also max load in the recipe. COAL was very short, at 3.180", which makes me think I should try get closer to the rifle's COAL which, coincidentally, matches the SAAMI max COAL spec for the caliber @ 3.330".

Regards,

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You've got the base load to do just that. Vary the length and test some more with that load. Good luck.

 

[Prerylyon]

**Update - went to range today - don't laugh too hard at my "group" [emoji23] **

So, I tried COALs of 3.320", 3.300", 3.260", 3.220"

Best group (see pic) was with 3.260". Chrono was behaving today (tried some tricks from others that really helped) and was recording 2,863 fps 15' away from the muzzle (some spread up and down from there). Target was at 100yrds.

Will see if this 3.260" COAL is repeatable; and if so, then step up and down to see if the group gets any better.

Regards,

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[Colorado Cowboy]

You are on the right track.

 

[alaska2go]

The closer to the lands can spike the pressure, thus causing slower speeds and signs of primer deformation & a sticky bolt. Speer reloading manual is pretty spot on with their data. Some bullets shoot better closer to the lands while others do not. I find that speer bullets like a little jump to the lands. While sierra's like to be a little closer to the lands. Nosler in my experience like a little jump also. I really like Speer bullets and have had good results with them in accuracy & terminal performance.

The picture of the group tells me that the load is not that good when it jumps 1-1/2" in elevation .... I like groups that produce 3 shots at the same elevation at 200 yards. Hince the ladder test.

Good luck

 

[Prerylyon]

Alaska and all,

Thank you for sharing your experience and advice.

In fact, @ the longest COAL this afternoon, 3.320", the velocity we chrono'd was below 2,800 fps consistently w/ the same 57gr RL-19 charge. We were puzzled by this. You have provided a compelling explanation. Brass showed no pressure signs; but the chrono told the story.

Regards,

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[Prerylyon]

Re: elevation of the shots

The 3.300" COAL had the most consistent elevation of all; they were all almost in a line, yet the "group" was larger. Wish I had a pic to share of that trial.

Regards,

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[Bonecollector]

I would reduce COAL and try 3.25, 3.20, & 3.15 and see what looks the best. From there, you can micro ladder.
I know this is going less than the Saami max number, but if you look back to where you started and where you are now it seems to makes sense. (if I am properly explaining). Every rifle is different as you are finding out. The process starts out fun, but can get frustrating.
I think you're going in the right direction. Keep us posted.

 

[Prerylyon]

BC,

All good.

The Speer recipe COAL of 3.180" $ucked @$$ on grouping last week in my rifle. 3.220" was sub-par today, compared to the 3.226" COAL-which on grouping merits alone-shot best, that Alaska takes issue with; nevertheless I truly appreciate yours and his opinions. I need help from experienced friends. [emoji5]

Will revist 3.260" & 3.300" COALs next week; if I can get to the range. Otherwise, will go w/ COAL of 3.226" for 'lopes next month-while not the greatest group, it will put an animal down.

Regards,

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[JimP]

Some people get obsessed with sub 1" groups out of their hunting rifles, and while a lot of rifles will shoot those kind of groups some will not.

Then you have to figure in the bullets. I have a Weatherby Vangard 25-06 that just loves 100 grain Barnes TTSX bullets but hates Hornady's except for their 117 grain ones. I prefer the TTSX so that works out great for me.

So there is a possibility that if you swapped bullets you just might shrink that group in half or even more.

 

[Slugz]

Does the rifle have the original barrel on it? 1980s? Any idea how many rounds went through it ?

After rereading the thread my thoughts lean towards ensuring the barrel is up to specs and no abnormal deformation etc etc.....IMO that rifle should be doing a lot better based upon your data given.

Those Speers are very forgiving and I would think it should be shooting better and or there might be another issue.