- This topic is empty.
-
Topic
-
bjornborud
I finally found time to shoot my 30 XCB rifle today, bringing along several loads that I had prepped after last week’s outing. Today I was going to shoot ball powders, both Hodgdon LeveRevolution (LvR) and Winchester 760 have given higher velocities compared to extruded powders in earlier trials. All HV shooting today was done using Tim Malcolm’s breech seater, as max powder capacity and highest possible MV was the goal. To recap, my 30 XCB rifle is a target rifle from the 1950s, built on an FN Mauser blind single shot action. The barrel is a new Shilen Match, 31 inches long, 1 in 14 twist. Tim Malcolm (Goodsteel) recently re-barreled and re-bedded the rifle.
I had devised a “ladder test” of sorts, to figure out at which MV the bullet/lube/powder charge combo would lose accuracy. Not to be confused with the Creighton Audette ladder test, this was simply a series of charges starting at a known level, increasing by 2 grains per charge for the LvR and 1 grain per charge for the W760. Here are the targets for these 2 “ladders”:
At this point I picked one charge from each “ladder” and shot a 10-shot group of each. I picked charges that I believed would stay together:
Finally I upped the charge of the LvR powder by one grain and shot another group. This turned out to be where accuracy went south:
I did not bother to measure this group.
I have to say that this outing was very encouraging, and it certainly proved to me that the NOE 310-165 FN (XCB) is an outstanding bullet, and that White Label 2700+ Carnauba Red is an outstanding lube.
With this shooting I consider myself done with the breech seater, I’m sending it to Larry Gibson in Arizona so he can use it with his Oehler Ballistics Lab to plot the pressure curves in some of these loads. After the 55 grain load of LvR today (MV 3316 fps) the bolt handle was hard to open and I didn’t increase the powder charge any further. Primers were starting to flatten, but I have seen them much worse on heavy jacketed loads.
bjornborud-
Replies
-
jonbaldwin
…snip All HV shooting today was done using Tim Malcolm’s breech seater, as max powder capacity and highest possible MV was the goal.
…snipI think I’ve seen a photo of Tim’s Breech seater on a rifle…somewhere?
BUT, I don’t have a “grasp” of the process ?Anyone have a link to where that is discussed ?
OR
Does anyone want to shed some light on this for me ?Is the bullet seated in the case first ?
OR
Is the bullet first seated into the throat? then the Case with powder inserted into the chamber?
OR
Is the Breech seater replacing the cartridge case ?Someone mentioned that damage to the bullet base (or GC) is lessened by the use of this technique/tool? WHY ?
Thanks so much in advance for any answers
Jonedited: Oh Yeah, Great shootin Bjorn !
Jon,
here’s a link to the CBA forum where we are discussing different breech seaters. Scroll down the page to a couple of posts by myself and Tim where there are pictures.http://www.castbulletassoc.org/forum/view_topic.php?id=11251&forum_id=63&page=3
frankelliott
At what speeds? I know the Silhouette designs have shot accurately, but it is usually slower speeds. This thread is about high velocity so where may I read the threads of the silhouette designs shooting accurately at 2500+ FPS?
This needs to be determined. There has only been one bullet tested at these velocitys. Until other bullets are tested (hopefully with the same rifle) we will never know what design excels at this velocity level.
Frank
At what speeds? I know the Silhouette designs have shot accurately, but it is usually slower speeds. This thread is about high velocity so where may I read the threads of the silhouette designs shooting accurately at 2500+ FPS?
This needs to be determined. There has only been one bullet tested at these velocitys. Until other bullets are tested (hopefully with the same rifle) we will never know what design excels at this velocity level.
Frank
Frank,
no doubt. And it will be determined in due course. But, as Larry says in post #20, at this point there are several basic trials that have to be concluded. It is way too easy to get sidetracked when trying to cover too much ground too quickly. I got sidetracked with lube (it netted me the addition of Lars 2700+ so I’m happy about that one), and I got sidetracked with alloys (yes, Lino shoots very well but was not really the alloy that was being discussed early in the XCB project).As for what was said by Asperly Aimless before he edited his post, I seriously doubt that any bore rider will succeed at the velocities that we are shooting the XCB bullet at.
richardshedd
As for what was said by Asperly Aimless before he edited his post, I seriously doubt that any bore rider will succeed at the velocities that we are shooting the XCB bullet at.
This I agree with. It has been claimed that the bullet (bore rider…specifically 190grX) will shoot better than the XCB, but the proof just isn’t floating around to prove the bore riders will shoot as well as the XCB bullet at high velocity.
Jon,
here’s a link to the CBA forum where we are discussing different breech seaters. Scroll down the page to a couple of posts by myself and Tim where there are pictures.http://www.castbulletassoc.org/forum/view_topic.php?id=11251&forum_id=63&page=3
Thanks Bjornb
Just in case anyone else has a lack of understanding as I did, this answers my question.Bjornb at CBA 11-25-2014
The reason I asked is that we are experimenting with breech seating in my 30XCB rifle (some of you may have read about the cartridge on the other CB forum), and to that end Goodsteel (the gunsmith who built all the XCB rifles) has fabricated a guided breech seater (FN Mauser action) that I’ll have in my hands sometime this week. The idea is to seat the bullet far enough to have it fully engraved (ie. all the way to the gas check), and to fire with a charged case using a small tuft of dacron to prevent powder spillage. The goal is high velocity, in the 26-2700fps range.
darrinwright
ianharris
This I agree with. It has been claimed that the bullet (bore rider…specifically 190grX) will shoot better than the XCB, but the proof just isn’t floating around to prove the bore riders will shoot as well as the XCB bullet at high velocity.
The AM 31-190X is NOT a “bore rider”. The nose in fact is almost identical to the later NOE 165 bullet.
Gear
timmalcolm
This I agree with. It has been claimed that the bullet (bore rider…specifically 190grX) will shoot better than the XCB, but the proof just isn’t floating around to prove the bore riders will shoot as well as the XCB bullet at high velocity.
The AM 31-190X is NOT a “bore rider”. The nose in fact is almost identical to the later NOE 165 bullet.
Gear
Gear, have you had the opportunity to try any NOE molds at HV?
stevendragonjr
Nice work. All this is well beyond my abilities. Maybe one day when I have a lot of free time I can learn to shoot like this.
If you know how to shoot, then you know all you need to know, and if you can break off enough time to do three or four range sessions, you’ve got it. There is no hocus pocus here or thousand yard walk on the rice paper. You screw a 14 twist barrel in your rifle, and get a mold that drops a perfect bullet to fit your chamber, use the alloys, and lubes outlined. Bingo. HV success.
The XCB rifles are just a way that I can control the internal dimensions of the chamber and be able to say “use the NOE bullet with the MBT rifle, load it like so, and you’ve got it by the tail”.
Bjorn has only been casting for 2 years, and was shooting 2500FPS a month after he got his rifle. What you see here is just us trying to see what is possible if everything is just so. Once we have a clear path forward, I will write a tutorial (or one of us will) on how to cut straight to HV accuracy, and take all the smoke and mirrors away for everybody.What we are trying to do is create a way that costs less, gets you there quicker, and has guaranteed success.
An alternative if you don’t feel like spending $600 and 3 years of trigger time to get results that sorta kinda not really but still sometimes work with a standard fast twist barrel.Keep an eye on it, we’re getting closer all the time, once a few more people take the plunge, I think you’ll see HV shooting becoming much more common place.
daveridenour
These threads have already been a great tutorial. Once all the testing is complete, it will really be something worth publishing!
Dave
It’s already in the works, in a small way. I’ve been asked by Al Nelson and Wiljen to do some writing for Castpics, and my plan was to collect all the data from the start of this project and turn it into a pictorial about the shooting that was done with my rifle. I’ll also re-shoot all the previous loads to account for what we now know was a bulged barrel when the shooting started.
I’m finishing up a house building project that’s been taking all my spare time, and the Castpics piece will be top priority following its completion.
jonbaldwin
frankelliott
richardshedd
darrinwright
ianharris
timmalcolm
stevendragonjr
daveridenour- You must be logged in to reply to this topic.