Longer 30 cal plain base question

[Marlin Junky]

Can something like the following design be stabilized at 1200-1300 fps with a 1:10" twist out to a couple hundred yards? As always, I'm looking for < 1MOA.

http://accuratemolds.com/bullet_detail.php?bullet=31-200E-D.png

Thanks for your opinions.

MJ

[Ben]

MJ

While my Modern Bond 190 gr. plain base has a different nose style, the other parameters are very similar with my speeds in the 1,300 fps zone.

You can see what my Modern Bond 190 is doing here :

http://castboolits.gunloads.com/showthread.php?170525-Modern-Bond-30-cal-190-gr-Plain-base

[Larry Gibson]

Yes.

Larry Gibson

[Marlin Junky]

Ben,

What's the length of your MB 190?

Which boolit would be easier to stabilize? The AM 31-200E or your MB 190?

I was thinking about trying the 31-200E with about 18-19 grains of Re7 for a nice soft shove to 1300-1350 fps. Or perhaps having 31-200E modified to incorporate a .200" meplat.

MJ

[RickinTN]

And another question for Ben and others. What approximate alloy do you recommend for the plain base bullets at the lower velocities?
Thanks,
Rick

[Marlin Junky]

And another question for Ben and others. What approximate alloy do you recommend for the plain base bullets at the lower velocities?
Thanks,
Rick

Basically, that's going to depend on the boolit's sectional density, the powder you intend to use and the chamber/barrel configuration AND condition. For example, given my Pre-64 M70 in 30-'06, a 200 grain PB boolit and enough Re7 to launch into the 1300 fps neighborhood, I'd start with an alloy similar in hardness to Lyman #2 or perhaps a tiny bit softer (less Sb). However, hardness isn't everything; i.e., the alloy composition makes a difference too. I like to keep a lot of 50/50 around (air cooled/aged BHN: 10-11) and heat treat for different applications.

Start soft with 50/50 and a proven lube; and, watch for excessive fouling. If you're not running clean enough, heat treat in a convection oven at 400F for 45 minutes and quench into cool water. That treatment is usually sufficient to move your BHN up a few points after a week of aging.

MJ

[44man]

I am just getting back into a rifle for cast myself after not having one in about forever. I really am finding a difference from my revolvers.
Just a 30-30 Marlin but I have shot some very soft boolits at 7BHN pretty fast, shot very well with no leading.
Other jobs and the weather have me behind so I can't define the rifle yet but it sure does not appear as picky as a revolver.
MJ has some good advise and 50-50 would be a good place to start and work with toughness enough to take rifling.
It has to be 50 years since I shot cast in rifles but my original 25-20 would do 3/4" at 100 yards with open sights and the .348 could head shoot chucks at 100 yards. The only gun I had trouble with was the Marlin in .35 Rem, the Lyman boolit was way too small.
It's funny that I have to learn again! :drinks:

[RickinTN]

MJ,
Thanks for your response. My apologies for taking your thread a little off course. I have the recent NOE group buy 311041 with a PB cavity and am casting with COWW + 2% tin air cooled. It drops @ around 180gr. Aging hasn't been a problem lately with our weather and my schedule. I'm thinking of starting with around 8grs. Red Dot which should be sub-sonic, and around 15grs. 2400 which should be slightly super-sonic and both which I think should produce somewhere <20,000cup. Hopefully these charges will be a good place to start.
Thanks for your help,
Rick

I probably should have mentioned this is in my Model 700 '06.

[Marlin Junky]

MJ,
Thanks for your response. My apologies for taking your thread a little off course. I have the recent NOE group buy 311041 with a PB cavity and am casting with COWW + 2% tin air cooled. It drops @ around 180gr. Aging hasn't been a problem lately with our weather and my schedule. I'm thinking of starting with around 8grs. Red Dot which should be sub-sonic, and around 15grs. 2400 which should be slightly super-sonic and both which I think should produce somewhere <20,000cup. Hopefully these charges will be a good place to start.
Thanks for your help,
Rick

I probably should have mentioned this is in my Model 700 '06.

RickinTN,

No problem, we're still talkin' about PB .30's... "longer" is totally subjective.

I'm very interested in your results and hope you post some targets. Hopefully your NOE '041 will size to a nice round .311".

MJ

[Marlin Junky]

I am just getting back into a rifle for cast myself after not having one in about forever. I really am finding a difference from my revolvers.
Just a 30-30 Marlin but I have shot some very soft boolits at 7BHN pretty fast, shot very well with no leading.
Other jobs and the weather have me behind so I can't define the rifle yet but it sure does not appear as picky as a revolver.
MJ has some good advise and 50-50 would be a good place to start and work with toughness enough to take rifling.
It has to be 50 years since I shot cast in rifles but my original 25-20 would do 3/4" at 100 yards with open sights and the .348 could head shoot chucks at 100 yards. The only gun I had trouble with was the Marlin in .35 Rem, the Lyman boolit was way too small.
It's funny that I have to learn again! :drinks:

Yeah, some of those old .35's went over .361" in the grooves and most of them made prior to '55 measured .360+ near the chamber.

Is your 30-30 Marlin an older 336 with "real" rifling, 44Man?

MJ

[HARRYMPOPE]

The Modern Bond is 1.125" long.
Sub MOA is fixed ammo with plainbase is not easy to achieve on a regular basis with production guns.You will often see pictures of very nice individual groups but seldom one target full of them.Breech seating is another thing altogether.


George

[RickinTN]

Most of my 311041's will contact about 75% or so of a .311 sizer, some a little less, and some up to 100%. I'm not sure if the variation in diameter of my bullets is due to my technique or if it's normal, I am new to this (been casting about 2 months).They will size completely @.310 and I have a couple of .308's that will not take larger than .310 I want to eventually try these in, not to mention the 336 fleet, both ballard and micro-groove, which as far as I know will all take .311 or larger.
Breech seating.......I'm not totally familiar with the technique but my cases are now sized to where I could probably seat the bullets with heavy finger pressure, so little that I am a little concerned about loaded rounds keeping their intended OAL during transport. I could just start the bullets after charging and let the bolt "finish" seating during chambering with minimal bullet engraving, which is what I may try. I am using a redding bushing neck die, so I can control the neck tension.
Any suggestions on my seating or other factors with these loads?
Thanks for the input,
Rick

[Marlin Junky]

Most of my 311041's will contact about 75% or so of a .311 sizer, some a little less, and some up to 100%. I'm not sure if the variation in diameter of my bullets is due to my technique or if it's normal, I am new to this (been casting about 2 months).They will size completely @.310 and I have a couple of .308's that will not take larger than .310 I want to eventually try these in, not to mention the 336 fleet, both ballard and micro-groove, which as far as I know will all take .311 or larger.
Breech seating.......I'm not totally familiar with the technique but my cases are now sized to where I could probably seat the bullets with heavy finger pressure, so little that I am a little concerned about loaded rounds keeping their intended OAL during transport. I could just start the bullets after charging and let the bolt "finish" seating during chambering with minimal bullet engraving, which is what I may try. I am using a redding bushing neck die, so I can control the neck tension.
Any suggestions on my seating or other factors with these loads?
Thanks for the input,
Rick

You should make an effort to bring the mold to a higher working temperature before going any further (add a hot plate to your tool kit if you don't already have one). Gas checks are like crutches in that they compensate for castings' shortcomings; e.g., "out-of-roundness".

A typical '06 chamber will need .311" boolits for the best performance; whereas, the typical .308 Winchester will handle .310" boolits better.

Since you're not likely going to be breach-seating ammo into your bolt guns, seat boolits into neck sized only brass such that the boolit just contacts the lands. I neck size '06 cases such that the first 0.1" of the neck adjacent to the shoulder is not touched by the die.

You can play with the pressure into the lands by adjusting COL +/- a few thousandths of an inch.

MJ

[williamwaco]

The Modern Bond is 1.125" long.
Sub MOA is fixed ammo with plainbase is not easy to achieve on a regular basis with production guns.You will often see pictures of very nice individual groups but seldom one target full of them.Breech seating is another thing altogether.


George

You will get a sub 2" group at 200 yards occasionally.

If you can do it every time, you need to write a book.


.

[Marlin Junky]

Here's a group I shot today in intermittent light rain, ambient was in the mid to high 50's.

12.5 grains of Blue Dot, 198 grain PB boolit about 1.08" long with a .2" meplat and dressed with MML. BHN was in the 14.5 to 15 range.

10 shots at 75 yards... orange dot is 1.25" in diameter.

Anyone have suggestions on how to improve on this accuracy? I'm thinking the alloy needs to be tweaked.

Velocity = 1327.

[Ben]

Marlin Junky

That looks very impressive to me.

As to Blue Dot,.....sometimes I think I want to buy a pound of it and try it.
At other times, I read about all the " spooky " things that Blue Dot is capable of with pressures and I head to some other powder.

Ben

[Marlin Junky]

Ben,

Too much paper remaining between the holes... I needs 'em to group tighter... 'specially at 75 yards.

I think Alliant Steel was created to address the pressure spike issues that are doggin' BD.

MJ

[popper]

MJ - my RD180 PB does that @ 50 ~ HT COWW with 14 gr 2400, mostly vertical stringing. filler should eliminate that. same alloy I use for full GC loads.

[HARRYMPOPE]

For me with plainbase the closer I get to 1400 the harder it gets to keep consistently small groups.Though yours look pretty good.I find that you can get one or two good ones but after about 25 shots things get worse and the point of impact shifts.When i had my 30-06 shooting plainbase pretty well it didn't seem to matter if it was Linotype,indoor range backstop lead or wheel weight.

[357maximum]

Don

Keep that group and shoot 2 or 3 more just like it over the course of several days. Then compare notes. Some of that windage in the group may have been you, bag technique or the weather...or all the above.

Groups with my bubba'ed spanish mauser 308 hackjob every so often looks just like that one you posted and I KNOW where the loose screw is located and what causes it to happen. Alot of the time I can ragged hole them, but the mean average group with this particular toy looks more like that one you posted ......they almost always look better when someone else is behind it rather than me for some reason ????????????????. The spaniard just does not like me somedays I spose.

[Marlin Junky]

Mike,

Ya know... it was windy yesterday. We were commenting that it was a good idea leaving the 22LRs at home. :bigsmyl2:

Also, I don't have the best optics on my '06 either (Leupold VX-II 2x7 set on 6X).

MJ

P.S. BTW, day to day, week to week variation in group size/shape is the reason I mothballed and/or sold most of my leverguns and went to bolters with optics attached... gettin' older can be a bummer. I don't drink coffee before my target sessions anymore, either.

[Marlin Junky]

Here's anonther...

Same boolit (198 grains in approx. BHN 15.0 alloy) wearing MML-Purple and shot with 15.0 grains of WC-820.

There was a wisp of alloy at the muzzle (after a total of 17 rounds) and it looks like I pulled a small piece of lead out on the cleaning patch. I believe the low shots were fired first. Unfortunately, I wasn't watching the progress through the spotting scope... just my VX-II @ 7X.

Velocity averaged 1406 fps for the ten rounds shot at 75 yards... calm winds... same 1.25" orange dot used for aiming.

So whadda ya think... alloy too hard for the powder charge?

MJ

[popper]

No unless you just want 1 hole

[Marlin Junky]

No unless you just want 1 hole

That's the goal.

MJ

[Marlin Junky]

I'm going to bump the charge to 15.5 grains of WC-820 this week, all else equal. Well, actually, I'm shooting the last boolits of the batch and they're about 1/2 grain lighter... so that could screw things up too; however, they're testing in the same hardness range (approx. BHN 14.5 to 15). I'm going to start from a squeaky clean barrel and shoot 2 foulers, followed by my 10 round string for group and stats. If the barrel remains clean after 12, I'll shoot another 8 at another target.

MJ

[kir_kenix]

I just got done shooting some groups in my 30BR today...mostly PB boolits. A PB 311041 (NOE), PB Lee 113 Soupcan (with GC and some with GC cavity removed), 170 gr RD with check cavity remove, 120 Gr PB GB I think was probably for the 30 Carbine, 93gr Lee PB that is probably intended for pistols, and a 195 gr PB GB from a few years ago. Loaded over a variety of powders, just to see what that 1:17 twist would do while fireforming 300 pieces of brass for this season.

I actually shot quite a few .75-1.00" groups, but I'm guessing I agged out somewhere around 1.75-2.00"...even if you exclude the 311041 and 195 grain GB that averaged over 2". I pushed some of the GC'd 113 soupcans (dressed with gc they weigh about 120 grs) to 3000 fps just to see what they would do. Turns out they will shoot inside 1.85" at 100 and 2.5" at 200...but did exhibit some tipping at 200. Probably will not revist 35.5gr's of Benchmark and this bullet again, but it was educational none the less. The 170 RD (seated pretty deep you might imagine) cut a few clusters under 1", but most were over 1.5".

I'm guessing your twist rate is more forgiving of long, heavy PB boolits than my short throated 30 BR with an ultra slow twist. Still I was hoping I could get some of the 195ers to do better at 1200-1300 fps. I didn't chronograph everything, mainly out of fear that I would forget an elevation adjustment and mangle my chrony.

Looking at my targets, the 93gr Lee could probably be made into a legitamate 1MOA load at 100 yards with my setup in the 1500fps range. Probably not worth the effort to me personally.

I wish I could report better results with the heavy boolits that were in your question, but today was not the day for that it seems. I will be taking my 308 and '06 out tomorrow, and I'll try some PB heavies to see how they do. I have some WC-820, and I'll try and duplicate some of the work you have been doing.

[Marlin Junky]

I wish I could report better results with the heavy boolits that were in your question, but today was not the day for that it seems. I will be taking my 308 and '06 out tomorrow, and I'll try some PB heavies to see how they do. I have some WC-820, and I'll try and duplicate some of the work you have been doing.

Definitely report back when you find an alloy that groups well in the 1400-1500 fps range. When I can put 10 into that orange dot at 100 yards, I'll be satisfied for quite some time. :bigsmyl2:

MJ

[Marlin Junky]

Below is today's result with 15.5 grains WC-820 (AA#9). I'm going to shoot for a little softer boolit next time I cast (hopefully this weekend). The round nearest the 1.25" orange dot was #4 from a cold, clean barrel (first 3 were shot at a different target) and below that, we have the next 8 rounds. I only shot 9 rounds at this target instead of the intended 10 because I had to extract one round from the chamber (I tried closing the bolt on a round that didn't have its rim under the extractor) by tapping on its nose with a cleaning rod; and, unfortunately, I didn't have a caliper available to check the COL after banging on the boolit's meplat.

I gave a friend some of these boolits and he shot a more "normally" distributed 10 round group from his H&H using 12 grains of Unique (1300+ fps).

The stat's were real bad too (with respect to the 15.0 grain load) which is further evidence the 15.0 grain load with the slightly heavier (and perhaps softer) boolits from last week was producing more consistent pressure.

Achieving the proper alloy for this type of shooting should prove rewarding.

P.S.... Forgot to mention that the lube was MML-Purple, which will be my lube choice until I get 10 rounds to fit inside the 1.25" orange dot at 100 yards, or until the temp breaks the 90F barrier before 10:00AM (when I will switch to MML-Red). Also worth noting is that I pulled a lot of boolit alloy out of my barrel near the chamber, at the end of the 20 round string; however, the problem is a matter of incompatible alloy for the powder charge, not a lube failure.

MJ

[Marlin Junky]

I'm going to return to this in the next couple weeks but will be burning 4759 instead of WC-820. If 4759 proves to be too slow for 1300 fps accuracy, I'll need to acquire some more shotgun powder and might have to go through the barter system at this point!

MJ

P.S. If anyone has an idea for a good plain base design specifically for the '06, let's hear about it. I'd like to have a custom high BC (long, tapered ogive) design with a 60% meplat in the 180-190 grain range cut by Accurate Molds this summer. I started on a couple versions some time ago, but would like to get some input from others before proceeding. Specifically, I'd like to get some input on how much lube the design should carry. I think with a plain base boolit the amount of lube is more critical than it is with a gas check design, all else equal, naturally.

Thanks!

[303Guy]

MJ, have you tried way slower powders? Not suggesting they would work better, just interested.

I'm seeing yaw in several of those boolit holes, especially that "fourth fouler". Could those boolits be canting a little on launch?

[Marlin Junky]

MJ, have you tried way slower powders? Not suggesting they would work better, just interested.
Not sure, I'm going to pull records right now to see what I can find. I probably should try some Re7 rather than 4759!


I'm seeing yaw in several of those boolit holes, especially that "fourth fouler". Could those boolits be canting a little on launch?

Yah know, this is what makes this hobby fun... I don't know! However, I would assume if I was getting "canting a little on launch" as you put it, I wouldn't be able to group at all at 75 yards. My run-out is virtually non-existent and the boolits are seated to touch the rifling with their .16" long, .311" wide leading bands. I don't recall exactly what the nose diameter is at the leading band junction but it was designed to be bore diameter. I thought I noticed the yaw on target too and was wondering if those particular boolits might be a little nose heavy for this velocity. I guess I haven't posted a pic of the castings from this particular custom mold yet, but it has a fairly long nose with a tangent ogive and a .2" meplat. 100 yard targets may be informative. I need to get some tighter groups at 75y before backing up to 100y though.

I'm in the processes of upgrading my plain base .30 caliber mold collection and want to create a design that I can use for small varmints... something with a 50% meplat might shoot more accurately and still have enough punch at 100-150 yards to be effective on feathered and furry fruit burglars. If the design is aerodynamic enough (at least .350 BC according to the following website: http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi) it should be barely supersonic at 200 yards if started at 1350 fps (given the right atmospheric conditions and 4000 ft elevation).

MJ

P.S. Addendum to 303Guy's powder question:

I was able to find some limited chronograph records for 4759 but no targets.

14 grains 4759; average vel:1165 fps (too slow!); standard deviation: 9.5 fps; number of shots: 7.

When I get it together with the '06 and this boolit in about a week, I think I'll try 16 grains of 4759 to get started again.

Also, I just submitted two designs to AM to be incorporated into the same mold block which are two and three groove versions of the same boolit. Both have an overall length of 1.055", a .140" long base, the same leading band and nose configuration, weigh approx. 185 grains, utilize a .180" meplat and have an estimated BC of .375. The two groove version will carry about 0.1 grain more boolit lube.