175gr Speer Deepcurl.

[SmokinJoe]

Based on what a guy has on hand, I'm really wanting to load these up for my 7mm rem mag. Only suitable powder I have is H4831. And Speer has not added this to thier manual as of yet and have a web source that only contains 3 different powders, none if wich anyone can find anywhere. Looked in 4 different manuals and can find similar bullets, but not the same, after making some comparisons I can see that this bullet seems to be loaded a little lighter.

So I guess my questions are,

1) would you just go and use the info from the lee manual for a 175gr jacketed? It does seem to be within other perimeters for other similar loads

2) if working up a load for this where would you start and where would you stop? the generic manual is minimum 55gr and max 58gr

[twofifty]

The closest I can get for you is Lyman 48th Ed. data
for a 175gr Speer Grand Slam soft point with H4831.

I don't know the various ways that the Grand Slam is different from the Deep Curl. Metallurgy? Bearing Length? Flat Base or Boattail? Enclosed base or not?
Cannelure? Different density?

Anyhow, for the 175 Grand Slam Lyman says the starting load is 53.7gr.
Max load is 60gr. Of H4831. In a 9.5" twist barrel.

This seems pretty close to what you've found so far in your research.
I'd find out more about the bullet construction and use that to guide you as to where to start.

ymmv

[SmokinJoe]

On speers website they are listing a .310 sectional density, a 496 BC, and tested it at 3.190 coal. And are stating the maximum coal is 3.290

[twofifty]

The BC and SD figures have more to do with flight and terminal ballistics, respectively.

What you're concerned with is Internal Ballistics: what happens combustion and pressure wise from ignition to the bullet engaging the rifling and leaving the muzzle.

COAL is nothing but a general guide as to what seating depth worked well in the particular action & barrel used by the Manual publisher's ballisticians.
COALs vary a fair bit in real life and a guy has to be careful not to have such a long COAL that the bullet starts off jammed hard into the rifling (this could lead to a pressure spike) although a reloader can gradually seat a bullet further out till the results are optimal. But too short a COAL can lead to an over-compressed load and feeding problems. In other words, COAL is a guide and is not cast in stone. Your rifle will tell you what COAL is best for that bullet.
Maybe someone else can pipe in with info on the soot technique to determine 'where' the lands are and what COAL might be a good starting point.

For example, Lyman gives a COAL (they actually call it a COL) of 3.260" for the 175gr Grand Slam. You have found that Speer's website calls for 3.290" for their 175gr Deep Curl.

A 3 hundreths of an inch difference, which is a hint those 175gr bullets are different in ways that might matter in regards to load and pressure. Or not.

Fun eh?

May I suggest you read a few more reloading manuals, the ones with a good front section on internal and flight ballistics? This will give you a better sense of what is a safe and useful start load for your rifle.

[Pudelpointer]

Just use the Lee manual data. Deep Curl is just a bonded cup/core bullet.

[SmokinJoe]

I have a bullet comparitor as well as an overall length gauge, I was stating what their coals were for pressure state. I'm new to reloading on my own, and I appreciate the advise of the seasoned vets. In the evening I usually spend most of my time reading or watching new things about guns, and reloading. And spend the rest of the time putting the info to use. Every now and then you find something new that gets the wheels spinning.

[twofifty]

PudelPointer gave you sensible advice.
You have a cautious thoughtful approach so things will work out just fine.

[SmokinJoe]

Going to load
4@ 55.5
4@ 56
4@56.5
4@57
4@57.5

And shoot them at 300, meanwhile watching for pressure signs, and see how they group. Break up the tents after for the next test.

I will post the results tomorrow evening

[duceman]

Originally Posted by twofifty

PudelPointer gave you sensible advice.
You have a cautious thoughtful approach so things will work out just fine.

not to mention common sense!

[skywrench]

FWIW, Speer states that the data for Deep Curls is entirely different that the data for the rest of their bullets and not to interchange it. Good bullets though, I have been using 160's for my 7 WSM with great success - among the most accurate I've tried.

[SmokinJoe]

So I shot the loads I made yesterday at 300 yards off of a sled. This is what I got

All loaded with h4831
Cases at 2.490
Oal at. 3.285
175gr Sierra Full Curl


55.5gr showed low pressure signs
56.gr Showed low pressure signs
56.5gr shot 1.057"
57gr shot .999"
57.5gr shot .830"

I indicated low pressure by the carbon built up around case neck and shoulder,

Sorry no chrono.

[Pudelpointer]

I would keep going for at least 3 more: 58.0, 58.5, 59.0.....

[Smokinyotes]

0.830" @300. I don't think you need to do any more load development.

[SmokinJoe]

It's actual reading is a group of 2.490 at 300. Translating into.830.

I just loaded more closer to the rifling at 57gr, 57.5gr, and 58. Just built a new target. The guy that builds our maps/survey plans at work doesn't get along with our plotter. So I get sheets of thick poster paper sometimes 16feet long and 4 foot wide.

Shooting these new rounds tomorow.

[JCP]

Something that I started doing in the last year was finding the powder charge that grouped the best for me then loading up a bunch of those all at the same coal and using a lee hand press I would change the seating depth at the range. It saved me many trips to where I shoot. Don't mean to derail just thought I'd throw that tip in there.

[SmokinJoe]

That's a great tip. I'm lucky tho, my range is 200 yards from my reloading bench. A guy should start a reloading "life hack" thread. Probably all kinds of great tips out there to make life easy.

[twofifty]

Looking forward to the next batch.

[SmokinJoe]

Originally Posted by twofifty

Looking forward to the next batch.

Nothing too exiting, the same powder amount tightened to ..670" and that's all she wrote. Gun is a sako 85. Heavier powder amount did not do as good. But on the bright side I found my load