The 35 XCB, the sledgehammer I've been waiting for

[Yodogsandman]

In post#1, 50gr of IMR4320 with the 35XCB boolit looked like it was close. I really thought that with a few tweaks, you'd have "the load". Have you tried powders on both sides of it on the burn chart?

[35 shooter]

Bjornb this probably won't help you a bit, but in the 35 whelen with the 358009 i wound up just barely kissing the lands on the nose for best results . I started with .151" engagement and could only get 2" 5 and 10 shot groups @ 100 yds. with it.
I really had to play with seating depth on that boolit and the more i backed off the better it got.

I have no idea if your chamber will allow you to go shorter or how you have it seated...just saying what worked for me. It worked out to avg. 1" @ 100yds. sometimes just under, sometimes just over. My load is just over 2200 fps.

I'm going through the same thing now with the 35xcb. It does not like engagement in my rifle at all. I'll try backing off and giving it a run at the rifling next.
Playing with the seating depth with that 358009 might help...it did for me, but i almost gave up on it first. Now it's one of my most accurate boolits in the whelen.

Good luck with it.

[runfiverun]

has anybody captured any of these boolits and examined them for trailing edge failure?
or looked at the depth relationships of the rifling.
or measured for set-back.?

something is waay off here, even in a 14 twist rifle 19-20 hundred fps should shoot well.

[Bjornb]

In post#1, 50gr of IMR4320 with the 35XCB boolit looked like it was close. I really thought that with a few tweaks, you'd have "the load". Have you tried powders on both sides of it on the burn chart?

That's correct, the 4320 load was excellent and very fast. My problems arose when I veered off into HUNTING type bullets. This meant casting softer bullets and also shooting blunt bullets, e.g. the RCBS/NOE 200 FN or the 358009. I'm now looking into drilling a small HP in the 35XCB bullet and using it for hunting, cast from Lyman #2. Not sure it's the right way to go, but I'm mulling it over with Goodsteel.

[Bjornb]

Bjornb this probably won't help you a bit, but in the 35 whelen with the 358009 i wound up just barely kissing the lands on the nose for best results . I started with .151" engagement and could only get 2" 5 and 10 shot groups @ 100 yds. with it.
I really had to play with seating depth on that boolit and the more i backed off the better it got.

I have no idea if your chamber will allow you to go shorter or how you have it seated...just saying what worked for me. It worked out to avg. 1" @ 100yds. sometimes just under, sometimes just over. My load is just over 2200 fps.

I'm going through the same thing now with the 35xcb. It does not like engagement in my rifle at all. I'll try backing off and giving it a run at the rifling next.
Playing with the seating depth with that 358009 might help...it did for me, but i almost gave up on it first. Now it's one of my most accurate boolits in the whelen.

Good luck with it.

Here's what I had to do to load the 358009: Since the bullet cast the nose at .3515 or thereabouts, I used a Buckshot nose sizer with a .350 bushing to get the long nose down to bore size, and then I loaded the bullet like a bore rider, with a seating depth of only about .300 inches. Otherwise it would have had the gas check below the neck, something I wanted to avoid. Maybe this is what caused the problems.

[Bjornb]

has anybody captured any of these boolits and examined them for trailing edge failure?
or looked at the depth relationships of the rifling.
or measured for set-back.?

something is waay off here, even in a 14 twist rifle 19-20 hundred fps should shoot well.

No, I wasn't able to recover any bullets. What puzzled me the most was that I'd get tight groups at 100 yards but only spray-n-pray at 200.

[runfiverun]

a super close look at group shape, and the holes themselves could also provide a clue.

[taco650]

Would HP'ing the XCB change the fight characteristics?

[oldblinddog]

a super close look at group shape, and the holes themselves could also provide a clue.

^^^^^
this

[Hamish]

a super close look at group shape, and the holes themselves could also provide a clue.

Run, what would be your diagnosis?

Not calling you out, but seeing these kind of "Read the tea leaves." kind of posts by more experienced cast shooters have always bothered me as they give no clue to anyone not already versed in whatever is being discussed. It's nice shorthand for conducting a private discussion among those already in the know, but leaves anyone else completely in the dark, and as the 35 XCB would seem to be having trouble gaining the same kind of initial success that the 30 XCB did, this would seem to be the perfect thread for that kind of diagnostic discussion.

[Bjornb]

Hamish,
I completely agree with your "read the tea leaves" statement. Cryptic comments like the one in r5r's post above makes me scratch my head. I am NOT a life long cast bullet shooter, and I need all the help I can get.

Specifically in this case the group shapes are no different than what I have seen numerous times while shooting cast and jacketed side by side. Jacketed tends to show more "controlled" groups, something I suspect occurs due to the better uniformity of the projectiles themselves. No gas checks or lube, harder bullets and so on.

As for the initial success of the 35XCB, let me just give a quick synopsis of the completely different approach that was taken with the 2 cartridges:

-The 30XCB was a joint project that started a long time before I was ever a member of this forum. Many current and former members collaborated, and the project benefited from a wealth of shooting trials by those involved (example: Larry Gibson had already completed many HV shooting trials using .308W rifles and a number of bullet designs that we were able to quickly duplicate in the 30 XCB rifles, cartridge and bullet design).

-The 35XCB currently exists only in my gun safe: I own 2 rifles. I have about 150 fire formed cases, and Tim Malcolm has maybe 20. Add to that the fact that ever since I started shooting the cartridge (in May of this year), I have spent most of my energy trying to develop a hard-hitting and reasonably accurate hunting load, and there has been preciously little time spent on velocity trials and accuracy shooting in the bench rifle.

At this point Tim is getting close to finishing his own rifle chambered in 35XCB; that will bring more data to the table.

The NOE 35XCB bullet is showing a lot of promise, but it has not yet been cast in the large number of alloys that I used for the 30XCB project, and it's therefore difficult to draw good conclusions.

So don't touch that remote, more news will be forthcoming. Maybe as soon as this weekend.

[taco650]

Bjornb,

I can only speak for myself when I say "I'm waiting with baited breath" for more info on your (& Tim's) results. I've been thinking about converting my old 30-06 to 35 Whelen but if the 35XCB works better and uses less powder in the process, I may go that route.

[cainttype]

Bjorn, if you're confident that shooter error isn't involved (and I'm sure you've eliminated the majority of that), the 200 yd holes might provide evidence of a stability issue by displaying even minor elongation.
A recovered projectile with inconsistant lube residue remaining could open groups without elongating holes.
You're already familiar with stringing issues, both verticle and horizontal.

If you want to use the test alloy, I'd probably try shooting these heavies without nose-sizing, even if the GC seats slightly lower than the neck, with some of the slowest powders you have that can bring the velocities near where you want. Deep-seated GCs aren't necessarily bad, and the extra nose support might prove to be an advantage.
I'd want to try to recover some of the casts in order to insure there isn't any lube chunks causing issues with balance.
If your impact holes display any tipping, I would attempt to increase velocities if possible. Low velocities and slow twist-rates may not be the problem, but it never hurts to keep those possibilities in mind.

[Bjornb]

I removed the scope this morning in order to try a different one (the only variable I could think of that hadn't been addressed). The rear scope mount (Leupold style) had caught one of the lateral adjustment screws at an angle and was definitely not tightened down the correct way.

Regardless, I installed new rings and also moved my large Weaver T36 scope over to the hunting rifle (it's a known quantity). On Saturday I plan to shoot the 2 loads that shot well in the bench rifle (50 grs. IMR4320 under both the Barnes 225 and the 35XCB bullet).

I hear you AJ, I'll definitely be doing some experimenting with the 358009 with the nose unsized. So far the target holes haven't shown any tipping or key holing.

At this time getting the rifle to shoot ANY load with consistency is priority one; I need to rule out rifle problems. Shooter error will always be a problem to some degree

[oldblinddog]

The rear scope mount (Leupold style) had caught one of the lateral adjustment screws at an angle and was definitely not tightened down the correct way.

Bjorn, use these: Weaver Grand Slam bases and Leupold QRW rings. You won't have any more problems.

[rockrat]

Took my 358 Win. to the range yesterday. Was advised to try 3031, but only had some Benchmark which is a bit slower. Patterns with all boolits.
Went again today and tried 4895 and H-380. Patterns with 4895 and the XCB and about 3" groups with the NOE 235 RD mould and same with the 35-200. Had loaded up only6 rounds with H-380. Gun is a Remington xr100 that JES rebored with 5 groove rifling and chambered in 358Win.
Shot the H-380 loads first. First shot was way low left, but expected it to be away from the aiming point as I had some leading in the barrel. Figured to just shoot it out. Next 5 shots were just left of the aiming point. If I would have caught the wind switch from lightly at 3 oclock to 10-15mph or so, at 8 oclock, might have had a better group. Last shot was about 1/2" to the right of the group

Last 5 went into 1.5" with the first 4 around an inch. Load was r-p cases, fired 4 times, 45.6gr H-380 powder, sparked by a ww LRmag primer. Loaded to just touch the lands. Alloy was linotype with 0.2% Cu., sized to 0.360". Forgot my chrony

[CJR]

Bjornb,

I have some comments on your 35XCB tight 100yd. groups and patterns at 200 yds. At first, I thought maybe the separation between CP and CG , on the 35 XCB bullet, was incorrect. So I did a quick check and the CP is where the drawing says it should be. Then I looked at how far the CG moves forward, when exposed to high presiure, and it did not place the CG in front of the CP. Therefore, I concluded the following:
1. The 35XCB taper + long ogive minimizes the effective bearing length.
2. Shorter bearing length CB can yaw/tilt excessively if shot with digressive powders (i.e. sharp spiked pressures which tilt/yaw the CB in the barrel)
3. Separation between CP & CG is only important AFTER the CB leaves the muzzle. The greater the CP-CG separation the stronger the gyroscopic restoring moment to pull an aerodynamically/wind yawed bullet back on the flight path so its axis is coincident with the flight trajectory. This instant gyroscopic correction keeps the CB on the flight path and promotes accuracy.

Here's what I suggest:
1. Use the hardest CB possible. This minimizes yaw/tilting of the CB while in the barrel.
2. Try a progressive powder, i.e W760. This starts the CB slower but gives a higher velocity than digressive powders. Digressive powders tend to tilt/yaw the CB before they start moving in the barrel.
3. Try another CB design with a long cylindrical shape and a short nose length. Something like the 311291 or Lee style CB. Seat them long to obtain more bore diameter engraving/guidance on the CB to minimize yawing/tilting while the CB is accelerating in the barrel.
4. Try hard to recover some fired 35XCB. If you have in-bore yawing/tilting, the engraved rifling marks on the recovered CB will clearly show that.

Bottom line- I suspect you have in-bore yawing/tilting. The yawed CB "cones" on muzzle exit, i.e. tip rotates in a circle and the base rotates in a circle as well. The rotating CB looks like an "hourglass". The CB flight spiral then increases in diameter as the range increases and patterns show up on targets at longer ranges.

Best regards,

CJR

[Bjornb]

Bjornb,

I have some comments on your 35XCB tight 100yd. groups and patterns at 200 yds. At first, I thought maybe the separation between CP and CG , on the 35 XCB bullet, was incorrect. So I did a quick check and the CP is where the drawing says it should be. Then I looked at how far the CG moves forward, when exposed to high presiure, and it did not place the CG in front of the CP. Therefore, I concluded the following:
1. The 35XCB taper + long ogive minimizes the effective bearing length.
2. Shorter bearing length CB can yaw/tilt excessively if shot with digressive powders (i.e. sharp spiked pressures which tilt/yaw the CB in the barrel)
3. Separation between CP & CG is only important AFTER the CB leaves the muzzle. The greater the CP-CG separation the stronger the gyroscopic restoring moment to pull an aerodynamically/wind yawed bullet back on the flight path so its axis is coincident with the flight trajectory. This instant gyroscopic correction keeps the CB on the flight path and promotes accuracy.

Here's what I suggest:
1. Use the hardest CB possible. This minimizes yaw/tilting of the CB while in the barrel.
2. Try a progressive powder, i.e W760. This starts the CB slower but gives a higher velocity than digressive powders. Digressive powders tend to tilt/yaw the CB before they start moving in the barrel.
3. Try another CB design with a long cylindrical shape and a short nose length. Something like the 311291 or Lee style CB. Seat them long to obtain more bore diameter engraving/guidance on the CB to minimize yawing/tilting while the CB is accelerating in the barrel.
4. Try hard to recover some fired 35XCB. If you have in-bore yawing/tilting, the engraved rifling marks on the recovered CB will clearly show that.

Bottom line- I suspect you have in-bore yawing/tilting. The yawed CB "cones" on muzzle exit, i.e. tip rotates in a circle and the base rotates in a circle as well. The rotating CB looks like an "hourglass". The CB flight spiral then increases in diameter as the range increases and patterns show up on targets at longer ranges.

Best regards,

CJR

CJR,
I don't disagree with much of what you're saying. The 35XCB has not been experimented with nearly as much as it needs to, and come winter I intend to rectify that. WW760 gave good velocity and acceptable accuracy in the 30XCB and could clearly stand a trial in the 35. As for bullets, there just aren't a lot of offerings in 35 caliber cast rifle bullets, and very few are "scaled up" from 30 cal.

Interesting about bullet hardness; the 30XCB shot best for me with linotype bullets, and I'm planning to cast up some NOE XCB bullets from lino and mono just to see what happens.

I tried to get in some shooting last Saturday, but only managed 2 series before the lightning alarm sounded and we had to clear the firing line. The rifle shot well, even though ES and SD with jacketed (Barnes X) wasn't very impressive. The full case load of AA4350 showed promise for accuracy even though it was found lacking in speed.

[Larry Gibson]

No, I wasn't able to recover any bullets. What puzzled me the most was that I'd get tight groups at 100 yards but only spray-n-pray at 200.

Bjorn

Was this with the 35 XCB bullet or the 358009 bullet? My understanding from reading the thread it was the 358009 that fell apart at 200 yards as mentioned in post #34(?).

Larry Gibson

[Bjornb]

Correct Larry, it was the 2250 fps loads with the 358009 over IMR3031 that fell apart at 200. I have to drive over 2 hours to a 200-yard range, so I only got to test at the distance this once. At this point I don't want to rush any hunting loads for the 35XCB (since I have other rifles), and especially since I need to try shooting the -009 without sizing the nose.

So these 2 strings were just meant as more testing, trying to shoot the same loads in two different rifles to compare the accuracy. But weather cut me short and I'll finish up another day.