Need help on RCBS mold issues

[Vulture]

I bought a used RCBS 7mm 145 SIL mold a while back and finally got some time to cast some bullets with it. I cast about 50 bullets with it and seated the gas checks and sized them and then I loaded about 10 rounds to do some testing and when I went to chamber a round in my MOA 7BR the round wouldn't drop in the chamber. I looked down in the chamber and checked to if something was in there, nothing there, looked at bullet and everything looks fine. Took loaded round and tried sticking nose of bullet down muzzle end of the barrel and the nose would not slide in the barrel. So I measured the nose area of the bullet and it measures .281" all the way back to the first band. I measured a bullet cast with a Lee mold and it measures .276" back to the first band. My question is does somebody have this same mold and what does yours cast the nose diameter at?

As a related issue I bought some cast and lubed bullets off a guy on gunbroker and they were the 7mm 168 version of the RCBS mold and they worked perfectly. Is their a difference in the nose diameters of the 145 and 168 versions of these molds?

I would buy the 168 version of this mold if the nose diameter is different but I don't feel like spending $80.00 on a test if a new mold has the same problem.

[Greg in Malad]

Vulture,
I have the same mould, and the same problems. RCBS must have ran a bad batch, mine was casting a .280 nose and a .282 driving band. I returned it to RCBS and they replaced it with one that cast a .280 nose and a .284 driving band, my lee mould has a .277 nose that fits snug in my remington 700. I returned the second mould sometime this summer and forgot about it until I read your post. I think I will call big green tomorrow.

[mooman76]

Mine also measures .280 - .281. I have had my mould for a few years.

[Vulture]

The front band on mine must be correct because when I sized them the band was burnished and it measures .285" , the correct diameter of the sizer die.

[243winxb]

Groove dia. on a 7mm should be .284" The chamber throat should be the same or larger. Seat you bullet deeper in the the case so you dont hit the leade/rifling. In other words i am guessing you have your COL to long or your rifle is chambered for short light J bullets. For the nose to fit the lands, the nose would have to measure about .278" or slightly smaller, if the lands are .003" high.

[Vulture]

I found one of the cast bullets that I bought off gunbroker. It is the 168 version and the nose diameter is .276". The nose fits perfectly in the bore, nice slip fit, which I think is correct. I think my molds nose has the problem.

If I were to seat the bullet so the round would chamber, the bullet would be half way down in the case and the neck of the cartridge would probably not grip the portion of the bullet left sticking out.

Sounds like Greg in Malad and mooman76 have the same problem I have.

[The Double D]

So what is the neck diameter of the loaded round and what is the neck diameter of the 7BR chamber.

Have you thinned the necks?

The BR is supposed to have tight necks

[243winxb]

Your .281" nose dia. is not going to get a whole lot smaller even if you play with alloy or keep the mould super hot, frosted to get more shrinkage. Do you know what is in your alloy your using?

[Vulture]

Thats why I think the mold has a problem. I am using wheel weights and adding maybe 10% tin in the form of solder. I don't think I could ever change my lead formula enough to shrink the nose diameter of the bullet .005" and keep the driving bands diameter enough to fit the chamber and the lead into the rifleing.

I have the Lee 7mm mold and it's nose diameter is .276" and it works fine. And the nose diameter of the bullets I bought from the guy off gunbroker measures .276" also. The only problem with the Lee mold is it casts a bullet that only weighs about 126 grains and I shoot IHMSA with this pistol and the Lee bullet leaves a few Rams standing sometimes. I need a little heavier bullet.

[243winxb]

Nothing left to do then but send the RCBS 7mm 145 SIL mold back for adjustment, or sell it like the last person did.

[Vulture]

I found one of the cast bullets that I bought off gunbroker. It is the 168 version and the nose diameter is .276". The nose fits perfectly in the bore, nice slip fit, which I think is correct. I think my molds nose has the problem.

If I were to seat the bullet so the round would chamber, the bullet would be half way down in the case and the neck of the cartridge would probably not grip the portion of the bullet left sticking out.

Sounds like Greg in Malad and mooman76 have the same problem I have.

[45-70 Chevroner]

Vulture: I also have an RCBS 145gr. Sil. double cav. mold. And the nose portion measures
.278" and the driving bands measure .285". My mold is about 15 years old. I use that bullet in my 7MM TCU Contender. and the nose will slide in the muzzle with a tight fit but that is with finger pressure and I can pull it back out with a little drag. I think I would contact RCBS about the problem as 243winxb suggested. I don't think it will make any difference if you bought it from someone else or not. RCBS is very good to work with and am quite sure they will make it right. That is unless the mold is beat all to heck.

[high standard 40]

I have heard of the issue before, several times. Many people who have this mold shoot IHMSA silhouette with it. The resolution many of them came up with was to push the bullet nose first into a size die intended for .270 bullets, .277" or .278" up to the front driving band in effect sizing only the nose. I also have this mold and use that bullet in my 7TCU Contender and an XP100 in 7BR with no issues. Nose diameter on my bullets comes out .279" as cast with wheel weight alloy + 2% tin. The MOA must be a tight throat chamber. My mold was purchased early this year new.

[runfiverun]

the rcbs mold is supposed to pour at 280x285.
the 168 gr version pours the same,it just has more bearing length. even my nei mold pours at 279x285.