Dasher Woes - Please Help!!
- Thread starter Snipers World
- Start date
CaptainMal
Silver $$ Contributor
Fellow at the range tested his Dasher today with Alpha brass. He came to me and showed me some hideous "proud" primers. He told me they were 450 CCI's. To me they told a story of a badly bushed firing pin or extreme high pressure or both. The rifle used a Stolle action and looked fine. We talked about the load he was testing and then he showed me some fired cases he had shot using Varget in Lapua brass and the same load. No issues at all.
Forget that Alpha stuff at the load he used. That brass must need a lower powder charge. He talked about the larger flash hole and was guessing that might be the problem.
I don't know. Just know what I saw.
Forget that Alpha stuff at the load he used. That brass must need a lower powder charge. He talked about the larger flash hole and was guessing that might be the problem.
I don't know. Just know what I saw.
sizing die is whidden and absolutely doing it's job on the 200 line sizing. Chamber is cut for .4707 and brass coming out .4710 - .4715. Ive been on phone with alpha for over hour and half now combined the measurements were all within spec. I am currently trying to source a small lot of lapua brass to test.
shoot4fun
Gold $$ Contributor
Proud primers? Before or after firing? I noticed when I started priming my Alpha brass that the pockets are well into the tight side and extra effort was required to seat the CCI450 properly. It is also (if one has used Lapua previously) plain to see that the Alpha flash hole is much larger than Lapua uses. Is that a bad thing? Didn't seem to be.
I normally shoot around 32.7 Varget in Lapua Brass and shot 32.2 or so with Alpha. My POI was visually same for both and I really think the heavier Alpha will take less powder. How much less is going to be dependent on the individual chamber.
One of the loads I shot was the Hornady 100 A-Tip with 32.5 Varget in Alpha brass. Even those cases didn't show excess pressure at the 200 line.
I do think that my next loading session the primers will be CCI400 and I'm thinking that may take care of the difference in the flat hole size.
The OP has a different problem than a brass issue. He just has to work it out.
CaptainMal
Silver $$ Contributor
After firing. Hideous flowing around the firing pin. Stupid proud.
That's an interesting thought and something that makes sense to me. A larger flash hole would promote more rapid ignition of a larger portion of the powder charge in the case. That would mean that more of the powder is burning sooner, prior to the bullet getting a chance to start traveling down the bore. Net result would be a smaller space for combustion, and higher pressure as a result.
Not necessarily the OP's situation, just a side comment.
swipe marks on the case head read pressure to me
shoot4fun
Gold $$ Contributor
I loaded down from my normal charge of Varget in early Alpha 6 Dasher tests. While I normally use 32.7-32-8 Varget with EPS 106 I dropped to 32.2 for that bullet in Alpha. I considered that the Alpha weighs a little more (less volume), has a larger flash hole than Lapua and that I was testing with virgin brass. Accuracy was excellent, there was no primer flow or flattening but I did see a slight (very slight) shiny spot from the ejector of my Curtis Vector's bolt. Measuring the case at the 200 line with blade mic and a pin gauge in the primer pocket gave me no indication that I exceeded pressure. I am going to load more of these and test them this weekend between 300-600 yards. My initial thinking was I should maybe substitute CCI400 for CCI450 primers to see what effect that may have but accuracy was hovering slightly +/- 1" for 3 shots at 300 yards from mag fed ammo and bipod rest.
capitainMal Tell the guy that's shooting the CCI 450 to try some BR.4's and put a little crush on them. I'm shooting 33.4 gr. Varget with a 103 VT. and I can go up over 34 grains before I start getting pressure. I've got some Peterson 6 Br. brass fire forum-ed That I'm hoping to try in two weeks.
Joe salt
Joe salt
CaptainMal
Silver $$ Contributor
His name is Mike Lowitz. I think he is on here. Just figured it was an issue with using Alpha brass with the large flash hole.
Now the BR4 uses the same cup thickness as the 450. Priming compound is the difference. What would be awful is if he used a 400. From what I saw that thinner cup would have ruptured and burned his bolt face.
Mike stopped after maybe 4-5 rounds as that is what he had in his big paw when he came to me. The were all the same and he quit the testing. Good for him and after consulting with me, he got his education. If he reads this, he gets more.
JEFFPPC
Gold $$ Contributor
For what it's worth, I read on this forum several years ago that although BR4 and 450 cups measures the same thickness, the BR4 cup is a stronger material. This could explain the difference. Use to shoot my PPCs very hot. Only primer that held up with bushed firing pins was BR4.
TylerFromMS
Gold $$ Contributor
I’ve been getting the same velocities with both brands of brass. I do believe the work hardening of the base of the Lapua from fireforming loads leads us to believe the Alpha is running into higher pressure quicker. Using a fireforming load for its first firing changed my results as far as pressure signs in subsequent firings.
New Alpha weighed within 4 grains of fireformed and chamfered Lapua.
I loaded up some of my Lapua brass that had been fired in my chamber, cut by the same person and same reamer:
Notice the scrapes near the head. I shot some of OPs brass and loads in my rifle and it ejected perfectly. I usually run the same load thereabouts, in both brands of brass, and it does pretty well. I’ve tested a node 1 grain higher that was also good, but I didn’t want to trash my brass that quickly.
Lapua, 3rd firing:
Alpha straight out of the box with only a mandrel ran through the mouth. Same load:
Do I trust the actual velocities of the Shotmarker? No. Do I trust the shots measured from the same Shotmarker at the same time with no change in setup to correlate? Absolutely. SD and ES has shrank significantly on 2nd and 3rd firings. I’ve repeated my results with a borrowed magnetospeed.
OP is waiting to hear back from the gunsmith today. I believe the winners were those that said a burr or tight spot in the chamber. The action and brass is solid.
New Alpha weighed within 4 grains of fireformed and chamfered Lapua.
I loaded up some of my Lapua brass that had been fired in my chamber, cut by the same person and same reamer:
Notice the scrapes near the head. I shot some of OPs brass and loads in my rifle and it ejected perfectly. I usually run the same load thereabouts, in both brands of brass, and it does pretty well. I’ve tested a node 1 grain higher that was also good, but I didn’t want to trash my brass that quickly.
Lapua, 3rd firing:
Alpha straight out of the box with only a mandrel ran through the mouth. Same load:
Do I trust the actual velocities of the Shotmarker? No. Do I trust the shots measured from the same Shotmarker at the same time with no change in setup to correlate? Absolutely. SD and ES has shrank significantly on 2nd and 3rd firings. I’ve repeated my results with a borrowed magnetospeed.
OP is waiting to hear back from the gunsmith today. I believe the winners were those that said a burr or tight spot in the chamber. The action and brass is solid.
TylerFromMS
Gold $$ Contributor
QuickLoad is a guide. I use it, as well. According to what changes you make in entering information, it changes the output. Using my cartridge length and barrel length, it is 60,321 psi at 32.5. That’s with the standard weighting factor.
So your saying with that QL. with me running 33.4 gr. Varget with a 103 VT. I'm up over 75,000 psi? I don't understand these numbers, not saying there not right, but with my Dasher I can go up to like 34.1 before I get any pressure. So please explain how that QL. program can decipher from one rifle to another? No WAY
Joe Salt
TylerFromMS
Gold $$ Contributor
His numbers are incorrect. I left the default settings as default and it’s nowhere near that. He posted about changing the weighting factors and appeared to folks that he went the opposite way in adjusting it. Over a chrono, QL gets me within about 20fps.
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.