rem 700 308, accurate cast load?

[wesson357]

Hi,
I have a new rem. 700 tactical sitting in a HS precision stock. With jacketed bullets, I get sub moa quite easily.

With cast loads however, the best I get is 1.5-2 moa. tried a lot for loads with 160gr and 185gr lee mold PC gascheck with 10 to 13gr of red dot and Trail boss too.
I load cast with a lot of old WW2 rifles to that level of accuracy (1.5-2 moa) with about the same loads and bullets and that satisfy me, but with a modern 700, I would expect better.

What kind of accuracy can you get with a 700 in 308???
Mat

[RickinTN]

Bullet fit, then bullet fit, and then again bullet fit. You have to be concerned with static and dynamic fit. I can see much studying and reading in your future. If your Remington 700 is capable of less than 1" groups with jacketed bullets that is a good sign. Many Remington 700's have chambers which are not concentric with the bore. Accuracy is hard to obtain when the bullet gets it's start sideways to begin with. As odd as it sounds a load with a custom 190 +/- grain bullet of my design that Tom at Accuratemolds cut the mold for me to fit the model 700's that I own is 7.8 grains of International Clays. I suspect Red Dot may do just as well but I haven't tried it. I borrowed that load from our very own Ben. A person could do well to study Bens' past postings. I don't notice as much from him as I used to.
Good Luck to you,
Rick

[Larry Gibson]

Those M700s came with both 10 and 12" twist barrels, which do you have?

Also, keep in mind it's the quality of the cast bullet that determine 90+ % of the accuracy below the 1 1/2 - 2 moa benchmark. To consistently get below that level of accuracy you must use an excellent alloy and learn to cast truly excellent quality bullets. They must also be properly weight sorted. Getting below that level of accuracy, particularly with 10 shot groups, is also seemingly elusive with PC'd bullets. The bullets must be a perfect fit and in perfect balance going into the chamber. I'm not seeing where a PC coating can be evenly applied.

[saleen322]

Those M700s came with both 10 and 12" twist barrels, which do you have?

Which is the preferred twist for the 308?

[RickinTN]

For higher velocity the 12" twist is preferred. For lower to mid velocities I don't think it much matters. My most accurate model 700, at least that I've fired cast bullets through is a 1-10" twist.
Rick

[Shopdog]

Maybe a year ago? this very topic came up....

I figured what the heck,stepped out the shop door and sent 10 downrange... no warm ups,no foulers... just 10 shots basically,fast as the bolt could be worked. 1st shot went high,then the group started... around #6 or 7 the I felt the breeze and sure enough,that's the one out to the left. IIRC, the furthest right edge shot was the next,held into the wind. Finished strong.

[popper]

Low fps jacketed also? I use real rifle powder for 308W. Recently did red dot in 30/30, fun but not MOA. Little better in 300BO. Both PB. Use GC in 308W, AR10 does near MOA @ 200. I don't use Lee molds anymore, changed to Accurate.
Ben's GS is doing all the shooting now.

[charlie b]

Not consistently below MOA but consistently below 1.5MOA. Note three different powders, vel 1800 to 2100fps. Top two targets are same load, different days. Except for the one, they are at 200yd.

Savage 12BVSS in .308 (10 twist). Bullet is Acc 31-210E, all powder coated.

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As Larry mentioned the bullet is important. I sort to 0.1gn most of the time.

[wesson357]

That's great groups you have!
Thanks for the advices, I'll start to better sort my bullets and I'll try some loads with thumble lubed bullets (I don't have a lub sizer).
My alloy is Lyman #2 made with pure component so, it should not be a problem.

[quilbilly]

One of the most accurate rifles I have is a 700. Right out of the box it was sub MOA and remains so with a 160 RNGC and 19.5 gr of 2400 powder. Recently, I started testing the rifle with 208 gr RNGC and the same powder charge and found it to be consistently 1.25" at 100 yards. The twist is 1/12". FYI - the boolits come from Lee molds and are lubed with Alox.

[charlie b]

I forgot to note. If you look at the targets they show the weight sort. The top two are sorted to a single weight, 211.2gn. The bottom two are a weight range. But, the third one is a 'heavy' range. Typically the heaviest bullets in a casting session will shoot better than lighter ones.

FWIW, this is not the only bullet that shoots well in the rifle. The NOE 165XCB, RCBS 165SIL, Lyman 311299 and Lee 180 have all performed well. I shoot the 210gn bullet because 1) it fits my bore the best and 2) I like shooting to 500yd (and sometimes 600). The 210gn bullet does that the best.

Last, Lee bullets. They are bore riders and the 180's I cast were a little undersize for my bore. Powder coating got the 180gn up enough in dia to fit the bore well, which is why I think I got decent groups with it. If the nose is too small for your bore they won't shoot well. When loading bore riders I like a snug fit in the bore, ie, it takes a bit of effort to remove a chambered round and sometimes the bullet will stick in the bore. I seat them such that the first drive band is engaging the rifling. And, yes, I nose size the bullets (for my rifle it is a .302 bushing, body is .310).

[Rapier]

I do not see, "I slugged my bore", at any point. So if you are shooting as cast, because you do not own a sizer according to your post, what in the world are you doing and who told you to do that?

A mould does not throw a round bullet, the sizer makes it round and uniform. You should be sizing to the actual groove diameter, to start, if that is not accurate, you can increase the size by .0005 to .001

But you need to slug the bore first. There are several posts about slugging a barrel on this site.

[Larry Gibson]

Which is the preferred twist for the 308?

The 12" twist is the preferred simply because at any velocity the RPM will be less than that of a 10" twist. Thus, the adverse effect, at any velocity, of the centrifugal force on any imbalances in the bullet during the external ballistic phase (in flight) will be less in a 12" twist barrel. Ergo, all else being equal, the 12" twist potentially will give better "accuracy" [actually "precision" is the correct term].

A311299 will stabilize at 800 fps in a 12" twist barrel.

Here's 4 consecutive 5 shot targets (was shooting for score, not groups) that still are moa or less at 100 yards. Rifle was my M70 Target rifle with 12" twist.

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[wesson357]

I do not see, "I slugged my bore", at any point. So if you are shooting as cast, because you do not own a sizer according to your post, what in the world are you doing and who told you to do that?

A mould does not throw a round bullet, the sizer makes it round and uniform. You should be sizing to the actual groove diameter, to start, if that is not accurate, you can increase the size by .0005 to .001

But you need to slug the bore first. There are several posts about slugging a barrel on this site.
I don't l have a lube die but, yes I have slugged the bore and sized the bullets .001 over size.

[saleen322]

The 12" twist is the preferred simply because at any velocity the RPM will be less than that of a 10" twist. Thus, the adverse effect, at any velocity, of the centrifugal force on any imbalances in the bullet during the external ballistic phase (in flight) will be less in a 12" twist barrel. Ergo, all else being equal, the 12" twist potentially will give better "accuracy" [actually "precision" is the correct term].

That makes sense. I have a similar M70 from a gun show, what looked like an ISU M70 because the receiver was factory set up for clip usage and the deep belly match stock that was ISU standard. Sometime it was rebarreled with a 1x12 Hart. Anyway it shoots lights out with 168 match bullets and just to try it, I loaded 5 cast 170 grain bullets with Unique at 100 yards. Not a great group but it does show some potential. A sample 168 jacketed target and my first attempt with cast bullets in it.
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[wesson357]

I noticed with my bullets, the "bore riding" nose engage the riflings. Does it makes a difference?
It's more bearing surface.

[charlie b]

That's what I want to happen with my bore riders. When I used conventional lube I'd tumble lube the bore riders as well. Don't know that it made much difference.

[wesson357]

Hi, I finally tested some new loads with an other powder (SR-4759). Same Lee RN 185gr and Lee 160gr bullet Size to .310 and sorted by weight.
Already much better!
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[rockrat]

I use AA2015 with a 188gr gc mould (called Hunter--NOE mould), visually sorted, but thats it. Sized .311" Velocity around 2200fps. Groups around 1/2" CTC @100yds for 3 shots. Narrow window with that accuracy. Fair groups to great groups back to fair groups was only about a 2 grains of powder window.

[RickinTN]

I noticed with my bullets, the "bore riding" nose engage the riflings. Does it makes a difference?
It's more bearing surface.

That is why it's called a bore rider. Yes, it should engage slightly. Not so much the bullet is difficult to chamber or won't chamber but enough you can "read" it on the bullet nose.
Good Luck,
Rick

[Rapier]

What is the very first thing you do before you make the first cast bullet?

You slug the barrel to measure the actual groove diameter, you never assume or just guess. Every barrel is a +or- specification.
About the only accuracy you will find is the groove diameter to .001 over the groove diameter. Different companies figure a bore rider differently from .004 to .006 or ever .008 difference, groove VS land diameter. if you measure your lands and groove after sluging, you get both numbers. You can size the front and the base both on a bore rider and most match shooters do exactly that.